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 | 
                                                2,935,532,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,660,130,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,813,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                270,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                550,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                256,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                3,799,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,810,570,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,700,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                5,867,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,144,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,925,345,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                47.06
                                                
                                             | — | — | 
                                                97.91
                                                
                                             | 
                                                56.40
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.647
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.620
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.624
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                -82,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                549,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                290,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -32,219,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,119,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -196,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -214,645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -159,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                3,443,897,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,755,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,553,087,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |