Key Financial Data Of Reporting Company
| Concept | As at 2024-03-31 | 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 | 2018-09-01 to 2019-08-31 | As at 2019-08-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | |||||||||||
| Business results of reporting company | |||||||||||
| Ordinary profit (loss) | — | — | 
                                                225,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,776,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -525,207,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -974,949,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -645,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | 
                                                223,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,779,060,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -527,107,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -976,849,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -511,602,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Share capital | — | 
                                                90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                90,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                92,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                70,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                70,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | 
                                                56,443,800
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                14,500
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                14,500
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                14,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                14,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | 
                                                4,500,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,277,539,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,056,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,023,087,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,999,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                4,909,123,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,498,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,271,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,172,898,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,155,061,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | 
                                                79.28
                                                
                                             | — | 
                                                -72.35
                                                
                                             | — | — | 
                                                -11,638.77
                                                
                                             | — | 
                                                -12,562.38
                                                
                                             | — | 
                                                -5,677.64
                                                
                                             | 
| Dividend paid per share | — | — |  | — |  |  | — |  | — |  | — | 
| Interim dividend paid per share | — | — |  | — |  |  | — |  | — |  | — | 
| Basic earnings (loss) per share | — | — | 
                                                3.96
                                                
                                             | — | 
                                                -39.78
                                                
                                             | 
                                                -3,016.58
                                                
                                             | — | 
                                                -6,884.75
                                                
                                             | — | 
                                                -4,927.57
                                                
                                             | — | 
| Diluted earnings per share | — | — |  | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.912
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.945
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.894
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.872
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.928
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | 
                                                0.051
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                543,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,704,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -14,696,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,975,637,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                4,799,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,254,958,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |