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 | 
                                                6,816,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,806,039,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,018,139,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                -205,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                664,308,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,512,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                -216,151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                290,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                72,633,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                -216,151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                290,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                72,633,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                6,390,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,616,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,398,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                9,516,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,215,027,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,441,619,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                -1.27
                                                
                                             | — | — | 
                                                1.71
                                                
                                             | 
                                                0.43
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.671
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.465
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.758
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                1,973,199,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,976,454,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,729,636,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -750,049,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -706,444,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -109,375,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -2,469,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,771,646,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,399,775,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                1,430,132,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,676,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,147,249,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |