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 | 
                                                233,357,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                329,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                255,379,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                11,799,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,437,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                8,065,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                8,124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,548,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                10,955,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,397,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,091,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                80,386,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                72,158,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                71,851,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | — | 
                                                147,543,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                143,200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                151,364,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | 
                                                327.65
                                                
                                             | — | 
                                                123.62
                                                
                                             | — | 
                                                330.16
                                                
                                             | — | 
                                                306.77
                                                
                                             | 
                                                112.11
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.544
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.504
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.475
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |