Key Financial Data Of Group
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Ordinary profit (loss) | 
                                                -915,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,426,891,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -599,036,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                315,508,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,232,656,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                402,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                425,820,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,474,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                490,779,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                -111.44
                                                
                                             | — | — | 
                                                -198.78
                                                
                                             | 
                                                -91.92
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.739
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.836
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.818
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                -1,066,826,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,279,615,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -619,048,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                207,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,853,195,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                211,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                349,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,417,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                436,811,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |