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 | 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 | 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 | — | — | — | — | — | — | — | 
                                                29,337,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                12,808,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,589,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,833,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                13,911,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                32,864,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,856,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,397,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                10,690,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,355,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | 
                                                2,594,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,243,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                717,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,044,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,504,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,476,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | 
                                                2,075,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,063,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,327,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -208,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | — | — | — | 
                                                2,499,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1,679,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,083,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,692,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -34,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | 
                                                10,054,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                6,307,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                7,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,471,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,710,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,981,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,097,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,476,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,911,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | 
                                                19,454,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                11,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                19,696,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,056,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,393,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,628,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                22,340,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,542,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,322,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,444,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | 
                                                657.98
                                                
                                             | — | — | — | — | — | 
                                                418.05
                                                
                                             | — | — | — | — | 
                                                520.37
                                                
                                             | 
                                                363.32
                                                
                                             | — | 
                                                339.27
                                                
                                             | 
                                                425.04
                                                
                                             | — | — | — | 
                                                284.21
                                                
                                             | 
                                                280.50
                                                
                                             | 
                                                166.10
                                                
                                             | — | — | 
                                                208.36
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | 
                                                137.57
                                                
                                             | — | — | — | — | 
                                                81.01
                                                
                                             | 
                                                34.19
                                                
                                             | 
                                                104.99
                                                
                                             | — | — | 
                                                68.45
                                                
                                             | — | — | 
                                                148.76
                                                
                                             | 
                                                73.83
                                                
                                             | 
                                                95.29
                                                
                                             | — | — | — | 
                                                -10.77
                                                
                                             | 
                                                -14.96
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — | 
                                                136.77
                                                
                                             | — | — | — | — | 
                                                80.54
                                                
                                             | 
                                                33.99
                                                
                                             | 
                                                104.37
                                                
                                             | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | — | — | 
                                                0.510
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.564
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.398
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.494
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.413
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.176
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.309
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.114
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | 
                                                0.234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.207
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.095
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.216
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.221
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.420
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.303
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.425
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | 
                                                4.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                7.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                12.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                5.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | 
                                                2,611,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,165,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                3,142,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,525,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,284,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | 
                                                -163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -430,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -620,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,116,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | 
                                                -3,244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -2,359,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -3,804,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,366,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                474,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | 
                                                907,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1,603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                731,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,693,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,065,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,085
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,226
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                347
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                329
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                369
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                110
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                373
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                382
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,301
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,262
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                377
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,296
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                401
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                88
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                91
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                35
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                32
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                123
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                46
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                135
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                186
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                46
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                119
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                40
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |