Key Financial Data Of Group
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | 
                                                2,670,408,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,056,464,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,487,995,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                473,743,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                928,505,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                525,104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                6,465,662,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,266,287,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,955,317,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                8,440,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,590,984,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,139,682,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                82.54
                                                
                                             | — | — | 
                                                152.26
                                                
                                             | 
                                                88.66
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.766
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.729
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.732
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                345,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                430,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -12,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -72,828,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -66,374,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -396,569,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -203,726,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -182,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                2,770,707,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,833,883,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,448,963,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |