Key Financial Data Of Group
| Concept | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | As at 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | — | 
                                                22,839,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                86,085,923,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                21,449,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                766,448,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,068,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                562,493,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | 
                                                477,396,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,274,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                319,483,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | 
                                                477,741,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,537,189,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                354,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                24,347,164,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,179,517,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,262,379,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                45,373,261,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                44,002,545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                43,641,511,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                41.28
                                                
                                             | — | 
                                                110.16
                                                
                                             | — | 
                                                27.62
                                                
                                             | 
| Diluted earnings per share | — |  | — |  | — |  | 
| Equity-to-asset ratio | 
                                                0.537
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.550
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.533
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |