Key Financial Data Of Group
| Concept | 2023-09-01 to 2024-08-31 | As at 2024-08-31 | As at 2023-08-31 | 2022-09-01 to 2023-08-31 | As at 2022-08-31 | 2021-09-01 to 2022-08-31 | 2020-09-01 to 2021-08-31 | As at 2021-08-31 | 2019-09-01 to 2020-08-31 | As at 2020-08-31 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||
| Business results of group | ||||||||||
| Ordinary profit (loss) | 
                                                -1,824,707,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                225,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,776,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -525,207,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -974,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                4,161,297,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,500,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,277,539,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,056,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,023,087,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                4,632,370,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,909,123,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,498,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,271,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,172,898,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | 
                                                61.44
                                                
                                             | 
                                                79.28
                                                
                                             | — | 
                                                -72.35
                                                
                                             | — | — | 
                                                -11,638.77
                                                
                                             | — | 
                                                -12,562.38
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                -31.11
                                                
                                             | — | — | 
                                                3.96
                                                
                                             | — | 
                                                -39.78
                                                
                                             | 
                                                -3,016.58
                                                
                                             | — | 
                                                -6,884.75
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  | — |  |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.898
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.912
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.945
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.894
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.872
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.051
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                -1,937,248,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                543,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,704,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -10,959,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -14,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                1,478,797,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,975,637,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                4,329,624,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,799,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,254,958,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | — | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | — | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |