Key Financial Data Of Group
| Concept | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | 2023-04-01 to 2023-12-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-12-31 | 2022-04-01 to 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | — | — | 
                                                4,315,004,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,004,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,571,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | 
                                                -32,068,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -602,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -459,784,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | 
                                                531,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                610,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                915,865,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | 
                                                2,222,667,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,366,866,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,730,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | 
                                                4.59
                                                
                                             | 
                                                -15.80
                                                
                                             | — | 
                                                -161.08
                                                
                                             | — | 
                                                -100.02
                                                
                                             | 
                                                -22.70
                                                
                                             | 
| Diluted earnings per share | — | — |  | — |  | — |  | — | 
| Equity-to-asset ratio | 
                                                0.239
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.258
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.335
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |