Key Financial Data Of Group
| 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 | 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 | 2024-04-01 to 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 group | ||||||||||||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | — | — | — | — | — | — | 
                                                179,922,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                44,372,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                55,846,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                171,345,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                65,871,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                174,358,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                37,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                117,539,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                32,313,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                107,648,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | — | — | — | — | 
                                                39,992,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,921,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                35,317,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,101,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                40,172,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,979,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,303,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,832,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | — | — | — | — | 
                                                15,722,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                13,971,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                15,025,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,977,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                7,284,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | — | — | — | — | — | — | — | 
                                                45,468,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                38,816,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                25,989,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,299,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,771,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | — | — | — | — | — | — | 
                                                354,323,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                115,159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                316,230,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                101,580,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                92,425,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                283,172,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                261,127,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                88,656,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                244,133,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                85,433,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | — | — | — | — | 
                                                463,639,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                182,224,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                411,406,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                168,551,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                160,079,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                379,889,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                348,561,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                150,812,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                324,197,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                146,608,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | — | — | — | — | — | 
                                                4,274.51
                                                
                                             | — | — | 
                                                1,790.96
                                                
                                             | — | — | — | — | 
                                                3,819.35
                                                
                                             | 
                                                1,579.86
                                                
                                             | — | 
                                                1,437.48
                                                
                                             | 
                                                3,434.50
                                                
                                             | — | — | — | 
                                                3,235.25
                                                
                                             | 
                                                1,375.71
                                                
                                             | 
                                                3,067.67
                                                
                                             | — | — | 
                                                1,325.65
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | — | — | — | — | 
                                                253.96
                                                
                                             | — | — | — | 
                                                65.62
                                                
                                             | 
                                                96.54
                                                
                                             | 
                                                225.68
                                                
                                             | — | — | 
                                                93.57
                                                
                                             | — | — | 
                                                242.48
                                                
                                             | 
                                                34.81
                                                
                                             | 
                                                144.66
                                                
                                             | — | — | — | 
                                                22.22
                                                
                                             | 
                                                116.75
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — | — | — | — | — |  | — | — | — |  |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | — | — | — | — | 
                                                0.571
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.632
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.575
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.603
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.577
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.560
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.576
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.588
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.587
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.583
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | — | — | — | — | 
                                                0.063
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.039
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.064
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.062
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.067
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.073
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.026
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.046
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.017
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.040
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | — | — | — | — | 
                                                19.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                77.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                39.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                36.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                14.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                97.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                23.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                215.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                40.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | — | — | 
                                                33,646,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                22,076,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                27,323,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                14,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,767,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | — | — | 
                                                -17,466,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -9,805,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -7,815,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -17,860,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -7,801,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | — | — | 
                                                -4,620,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -7,542,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -6,599,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,403,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,441,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | 
                                                88,987,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                77,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                71,315,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                57,390,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                63,364,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                71
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                44
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                273
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                183
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                26
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,324
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                57
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,764
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                434
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,532
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                424
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                412
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,488
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,456
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                401
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,371
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                381
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                417
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                36
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                479
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                563
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                576
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                654
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                41
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                616
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                35
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |