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 | 
                                                65,881,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                80,171,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                53,830,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                3,200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,127,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,748,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                2,143,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,480,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,151,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                2,503,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,128,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                36,695,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                35,380,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                34,754,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                75,917,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                78,941,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                69,289,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                166.68
                                                
                                             | — | 
                                                41.01
                                                
                                             | — | 
                                                193.16
                                                
                                             | — | 
                                                89.68
                                                
                                             | 
                                                81.34
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.483
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.448
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.502
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |