Key Financial Data Of Group
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | — | 
                                                8,127,675,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,936,064,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,515,692,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                326,752,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                989,719,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                569,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | 
                                                230,449,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                704,543,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                399,013,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | 
                                                291,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                944,933,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                550,488,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                15,359,022,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,262,760,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,868,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                21,595,227,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,659,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,220,318,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                25.97
                                                
                                             | 
                                                79.40
                                                
                                             | — | — | 
                                                44.97
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.711
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.705
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.701
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                588,789,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,274,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                583,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -706,689,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -193,394,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -189,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -203,784,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -135,291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -125,302,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                5,355,295,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,634,863,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,948,092,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |