Key Financial Data Of Group
| Concept | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | 2023-07-01 to 2023-09-30 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2022-04-01 to 2022-09-30 | As at 2022-09-30 | 2022-07-01 to 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | 
                                                2,843,858,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,004,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,002,326,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | 
                                                -74,347,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -602,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -367,719,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets | — | 
                                                508,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                610,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,029,278,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | 
                                                2,188,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,366,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,722,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | 
                                                -20.39
                                                
                                             | — | 
                                                -6.07
                                                
                                             | — | 
                                                -161.08
                                                
                                             | 
                                                -77.32
                                                
                                             | — | 
                                                -39.24
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  |  | — | — | 
| Equity-to-asset ratio | — | 
                                                0.233
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.258
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.378
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                -13,212,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -582,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -334,627,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -41,345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -119,118,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -70,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -36,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                108,415,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                40,398,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                284,387,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                375,329,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                603,426,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |