Key Financial Data Of Group
| Concept | 2023-04-01 to 2023-12-31 | As at 2023-12-31 | 2023-10-01 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 | 
                                                13,459,343,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                15,414,519,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,501,361,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                265,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -95,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -73,549,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                179,524,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -72,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -31,884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                241,143,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -51,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -57,520,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                10,900,966,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,782,302,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,776,743,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                18,945,985,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,359,870,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,709,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                29.85
                                                
                                             | — | 
                                                19.53
                                                
                                             | — | 
                                                -11.86
                                                
                                             | — | 
                                                -5.22
                                                
                                             | 
                                                1.93
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.575
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.586
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.544
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |