Key Financial Data Of Reporting Company
| 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 reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | — | 
                                                8,548,710,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                37,304,148,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,512,385,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                462,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,970,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                485,041,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                19,656,946,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                20,021,181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,118,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                34,043,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                33,687,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                32,281,120,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                14.53
                                                
                                             | — | 
                                                102.18
                                                
                                             | — | 
                                                17.28
                                                
                                             | 
| Diluted earnings per share | — |  | — |  | — |  | 
| Equity-to-asset ratio | 
                                                0.571
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.587
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.555
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |