Key Financial Data Of Reporting Company
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | 
                                                24,026,716,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,867,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,551,933,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,246,170,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,876,877,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,890,439,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,738,154,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,509,942,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Operating revenue | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                5,111,461,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,384,769,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | — | — | — | — | — | 
                                                7,887,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,402,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                236,615,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,265,098,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,984,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,246,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,904,450,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,932,172,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                969,678,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,588,856,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                3,260,601,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -239,436,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,883,807,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,690,919,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                668,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | — | — | — | — | — | 
                                                4,978,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                4,978,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,978,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,978,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,978,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | — | — | — | 
                                                11,961,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                11,961,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                11,961,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                11,961,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                11,961,100
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | — | 
                                                21,428,211,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                13,570,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                17,735,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,456,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,647,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,334,361,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                11,872,879,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,396,842,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,386,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,122,490,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | 
                                                29,527,373,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                17,424,448,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                25,828,326,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,525,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,653,800,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,605,292,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,353,010,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,324,609,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,561,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,181,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | 
                                                1,822.06
                                                
                                             | — | — | — | 
                                                1,153.89
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                1,508.08
                                                
                                             | 
                                                974.18
                                                
                                             | — | 
                                                1,075.44
                                                
                                             | 
                                                1,218.86
                                                
                                             | — | — | — | 
                                                1,009.55
                                                
                                             | 
                                                884.05
                                                
                                             | 
                                                883.14
                                                
                                             | — | — | 
                                                775.69
                                                
                                             | 
| Dividend paid per share | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                210.0
                                                
                                             | — | 
                                                90.0
                                                
                                             | — | — | — | 
                                                80.0
                                                
                                             | — | — | — | 
                                                40.0
                                                
                                             | — | — | — | — | 
                                                30.0
                                                
                                             | — | — | 
| Interim dividend paid per share | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                70.0
                                                
                                             | — | 
                                                40.0
                                                
                                             | — | — | — | 
                                                30.0
                                                
                                             | — | — | — | 
                                                15.0
                                                
                                             | — | — | — | — | 
                                                10.0
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | — | — | 
                                                430.92
                                                
                                             | — | — | — | — | — | — | 
                                                277.25
                                                
                                             | — | 
                                                -20.36
                                                
                                             | 
                                                327.49
                                                
                                             | — | — | 
                                                245.21
                                                
                                             | — | — | 
                                                255.25
                                                
                                             | 
                                                143.78
                                                
                                             | 
                                                140.11
                                                
                                             | — | — | — | 
                                                56.88
                                                
                                             | 
                                                94.10
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — |  | — | — | — | — | — | — |  | — |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | — | 
                                                0.726
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.779
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                0.687
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.789
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.716
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.731
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.726
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.726
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.827
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.816
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | 
                                                0.259
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                0.261
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -0.020
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.240
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.250
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.229
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.173
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.148
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.076
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.114
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | 
                                                11.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                17.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                9.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                31.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                19.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                0.757
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.326
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.278
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.527
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | 
                                                6,001,678,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                3,281,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3,113,333,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,406,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,607,756,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | 
                                                -1,883,886,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                -194,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -788,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,100,942,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -321,061,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | 
                                                -700,473,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                -213,343,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -773,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                832,588,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -236,173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | 
                                                12,647,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                9,373,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,096,888,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,458,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,089,982,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                58
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                227
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                350
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                174
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                58
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                114
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                310
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                49
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                215
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                293
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                273
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                197
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                203
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                178
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                120
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                138
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                146
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                120
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                120
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                76
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                76
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                64
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                64
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | — | — | — | 
                                                3.499
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                3.674
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.761
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.915
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.206
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | — | — | — | — | — | 
                                                2.134
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                2.168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.534
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.450
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.421
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |