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 | 
                                                19,592,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                27,164,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,306,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                1,482,630,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,898,253,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                843,193,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                994,104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,275,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                577,154,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                1,023,747,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,214,393,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                419,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                17,077,335,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,443,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,649,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                27,934,902,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                29,115,187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,560,534,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                108.61
                                                
                                             | — | 
                                                47.89
                                                
                                             | — | 
                                                139.57
                                                
                                             | — | 
                                                63.15
                                                
                                             | 
                                                29.88
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.611
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.565
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.637
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |