Key Financial Data Of Group
| Concept | As at 2023-09-30 | 2023-07-01 to 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-09-30 | 2022-07-01 to 2022-09-30 | 2022-04-01 to 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | — | — | 
                                                8,515,692,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,674,769,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,601,126,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | 
                                                569,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                568,627,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                306,345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | — | 
                                                399,013,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                420,591,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                224,915,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | — | 
                                                550,488,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                594,726,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                300,128,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                14,868,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                14,433,179,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                14,138,582,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | 
                                                21,220,318,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                20,502,915,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,439,390,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | 
                                                23.71
                                                
                                             | 
                                                44.97
                                                
                                             | — | 
                                                47.28
                                                
                                             | — | 
                                                19.97
                                                
                                             | 
                                                25.23
                                                
                                             | 
| Diluted earnings per share | — | — |  | — |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.701
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.704
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.727
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                583,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,129,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                587,318,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -189,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -496,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                817,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -125,302,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -200,874,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -193,647,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                4,948,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,650,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,424,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |