Key Financial Data Of Group
| Concept | As at 2025-01-31 | As at 2025-01-31 | As at 2025-01-31 | As at 2025-01-31 | As at 2025-01-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 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 | As at 2022-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||
| Net sales | — | — | — | — | — | — | — | 
                                                1,651,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,567,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,343,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,681,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                601,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                542,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | 
                                                -1,373,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,490,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -1,455,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,453,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,792,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,611,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,764,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | — | 
                                                -4,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -4,117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Comprehensive income | — | — | — | — | — | — | — | — | 
                                                -3,931,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -3,707,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Net assets | — | — | — | — | — | — | — | — | — | 
                                                4,854,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,610,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,789,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,786,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,816,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,983,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                20,283,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | — | — | — | 
                                                14,241,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,752,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,204,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,532,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,714,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,812,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,144,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | — | — | — | — | 
                                                256.68
                                                
                                             | — | 
                                                403.48
                                                
                                             | — | 
                                                572.40
                                                
                                             | 
                                                465.56
                                                
                                             | — | — | 
                                                9,192.52
                                                
                                             | — | 
                                                69,537.06
                                                
                                             | — | 
                                                75,122.55
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | 
                                                -168.92
                                                
                                             | 
                                                -215.24
                                                
                                             | — | — | — | 
                                                -272.02
                                                
                                             | — | — | 
                                                -236.25
                                                
                                             | 
                                                -69,446.76
                                                
                                             | — | 
                                                -5,960.84
                                                
                                             | — | 
                                                -6,785.32
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — |  |  | — | — | — |  | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | — | — | — | 
                                                0.339
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.482
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.561
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.473
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.322
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.832
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.916
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | 
                                                -3,166,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -4,946,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | 
                                                -842,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -1,928,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | 
                                                159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                7,119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | 
                                                10,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                13,594,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
| Number of employees | 
                                                151
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                72
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                72
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                225
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                74
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                258
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                64
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                71
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                214
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                62
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                43
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |