Key Financial Data Of Group
| Concept | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | 
                                                3,492,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,462,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,850,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                118,385,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,712,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,800,989,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                65,496,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,954,414,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,966,480,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                64,071,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,952,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,966,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                422,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                352,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                319,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                2,732,274,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,782,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,964,337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                16.28
                                                
                                             | — | — | 
                                                -488.27
                                                
                                             | 
                                                -493.58
                                                
                                             | — | 
| Diluted earnings per share | 
                                                16.27
                                                
                                             | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.0973
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0726
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0617
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                73,073,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -933,675,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -858,505,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                274,406,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -652,226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -152,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                96,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                748,908,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                454,808,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                972,130,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                528,651,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                809,095,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |