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 | 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 | — | — | — | — | — | — | 
                                                45,686,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                28,658,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                27,923,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,819,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                30,356,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                55,922,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,758,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                31,450,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,874,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | 
                                                3,344,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                10,182,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,437,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,413,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,820,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,271,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,825,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                16,414,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,232,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,739,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,990,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,605,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | — | — | — | — | — | — | 
                                                2,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                2,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | — | — | — | — | 
                                                140,206,002
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                46,735,334
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                46,735,334
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                46,735,334
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                46,735,334
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | — | — | — | 
                                                85,768,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                76,612,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                82,419,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                66,003,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                59,954,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                77,946,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                74,365,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                58,114,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                72,266,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                57,734,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | 
                                                103,457,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                89,782,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                97,871,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                76,397,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                75,911,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                97,148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                96,249,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                75,156,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                91,092,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                73,702,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | 
                                                616.52
                                                
                                             | — | — | 
                                                556.56
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                604.94
                                                
                                             | 
                                                489.47
                                                
                                             | — | 
                                                444.61
                                                
                                             | 
                                                572.79
                                                
                                             | — | — | — | 
                                                546.65
                                                
                                             | 
                                                430.97
                                                
                                             | 
                                                531.55
                                                
                                             | — | — | 
                                                428.15
                                                
                                             | 
| Dividend paid per share | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                39.19
                                                
                                             | — | 
                                                78.00
                                                
                                             | — | — | — | 
                                                19.00
                                                
                                             | — | — | — | 
                                                19.00
                                                
                                             | — | — | — | — | 
                                                11.00
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | — | — | — | 
                                                61.96
                                                
                                             | — | — | — | — | — | — | 
                                                121.60
                                                
                                             | — | 
                                                46.22
                                                
                                             | 
                                                29.82
                                                
                                             | — | — | 
                                                20.32
                                                
                                             | — | — | 
                                                23.24
                                                
                                             | 
                                                14.76
                                                
                                             | 
                                                22.76
                                                
                                             | — | — | — | 
                                                11.91
                                                
                                             | 
                                                6.07
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — |  | — | — | — | — | — | — |  | — |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | 
                                                0.820
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.853
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                0.833
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.864
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.790
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.795
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.766
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.773
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.787
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.783
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | 
                                                0.100
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                0.230
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.099
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.051
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.046
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.042
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.034
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.042
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.029
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.012
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | 
                                                9.25
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                4.71
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10.13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15.69
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.65
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                10.18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14.05
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9.11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                20.51
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                40.27
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                0.218
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.563
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.429
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.308
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | 
                                                44,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                6,087,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,655,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,137,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,424,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | 
                                                23,200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                4,062,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,223,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,103,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                105,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | 
                                                -6,631,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                -2,173,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,341,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -983,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,052,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | — | 
                                                59,809,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | 
                                                43,343,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                35,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                33,037,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                30,866,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                463
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                404
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,283
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                715
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                589
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                147
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                101
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                67
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,474
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                852
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                864
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,582
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,599
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                871
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,571
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                880
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                41
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                107
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                77
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                44
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                123
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                55
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                33
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                154
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                170
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                34
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                176
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                41
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | — | — | — | — | 
                                                3.696
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                2.939
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.457
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.251
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.428
                                                
                                                    
                                                        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
                                                    
                                                
                                             |