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 | 
                                                12,140,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                15,736,099,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,589,264,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                528,627,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                344,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -22,226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                331,816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                148,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -84,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                469,512,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                158,785,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                62,972,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                15,813,340,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,405,266,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,320,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                32,492,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                31,294,129,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                31,409,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                96.14
                                                
                                             | — | 
                                                31.67
                                                
                                             | — | 
                                                43.02
                                                
                                             | — | 
                                                -24.36
                                                
                                             | 
                                                -4.87
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.482
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.488
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.483
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |