Key Financial Data Of Group
| Concept | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 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 | — | 
                                                50,624,704,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                18,369,919,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,808,784,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,623,725,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,473,174,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                43,765,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,256,597,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                34,521,523,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,481,026,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Operating revenue | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,274,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | — | 
                                                350,410,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                632,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,618,846,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,709,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,033,541,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -405,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                532,059,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                955,223,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                452,385,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,530,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | 
                                                -616,157,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                1,001,355,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,553,427,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                431,068,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,144,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | 
                                                368,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                1,198,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -754,456,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                757,832,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,158,325,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | 
                                                10,098,037,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,269,541,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,813,485,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,241,555,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,974,982,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,711,181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,735,178,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,805,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,335,698,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,216,698,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                37,397,010,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                27,545,243,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                36,092,535,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,541,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                30,761,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,903,513,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                31,781,037,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,274,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                28,973,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                20,104,222,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | 
                                                748.58
                                                
                                             | — | — | — | — | — | 
                                                539.40
                                                
                                             | — | — | — | 
                                                727.14
                                                
                                             | 
                                                611.53
                                                
                                             | — | 
                                                517.55
                                                
                                             | 
                                                645.91
                                                
                                             | — | — | — | 
                                                722.35
                                                
                                             | 
                                                727.56
                                                
                                             | 
                                                692.71
                                                
                                             | — | — | 
                                                461.28
                                                
                                             | 
| Basic earnings (loss) per share | — | 
                                                -45.72
                                                
                                             | — | — | — | — | — | 
                                                -62.25
                                                
                                             | 
                                                93.74
                                                
                                             | 
                                                74.30
                                                
                                             | — | — | 
                                                -188.28
                                                
                                             | — | — | 
                                                -115.26
                                                
                                             | 
                                                284.60
                                                
                                             | 
                                                31.99
                                                
                                             | — | — | — | 
                                                33.17
                                                
                                             | 
                                                159.09
                                                
                                             | — | 
| Diluted earnings per share | — |  | — | — | — | — | — |  |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | 
                                                0.270
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.264
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.289
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.227
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.236
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.306
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.347
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.322
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.309
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.166
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.108
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.479
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.045
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.073
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.255
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                23.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                35.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                851,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                1,368,989,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,271,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,029,812,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,654,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -955,469,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                -835,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -864,448,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -4,585,247,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -2,329,114,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                141,477,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                -1,505,362,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,524,997,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -789,068,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,014,648,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                3,438,718,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | 
                                                3,191,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,683,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,145,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,284,249,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                1,457
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                675
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                479
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                115
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                782
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                594
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,416
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                536
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                597
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,310
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                644
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,069
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                58
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                237
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                158
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                173
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                247
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                203
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                194
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                208
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                196
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                175
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                119
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |