Key Financial Data Of Reporting Company
| Concept | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | 2022-10-01 to 2023-09-30 | As at 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 | — | 
                                                440,266,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,155,988,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                331,781,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                35,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                76,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                26,674,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) | — | — | 
                                                53,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                18,198,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                804,012,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                688,574,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                652,838,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                1,306,539,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                932,040,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                947,436,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                17.65
                                                
                                             | 
                                                48.66
                                                
                                             | — | — | 
                                                16.89
                                                
                                             | 
| Diluted earnings per share | — | 
                                                17.41
                                                
                                             | 
                                                47.79
                                                
                                             | — | — | 
                                                16.55
                                                
                                             | 
| Equity-to-asset ratio | 
                                                0.500
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.739
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.689
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |