Key Financial Data Of Reporting Company
| 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 reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | 
                                                2,884,609,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,852,954,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,393,736,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                55,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -482,079,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -295,546,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | 
                                                66,697,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -599,743,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -447,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Equity in earnings (losses) of affiliates if equity method is applied | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Share capital | — | 
                                                156,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                156,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                156,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | 
                                                5,500,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                5,500,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                5,500,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | 
                                                3,376,029,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,449,216,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,716,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                6,844,027,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,953,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,020,800,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Dividend paid per share | 
                                                20
                                                
                                             | — | — | 
                                                41
                                                
                                             | 
                                                20
                                                
                                             | — | 
| Basic earnings (loss) per share | 
                                                12.24
                                                
                                             | — | — | 
                                                -110.07
                                                
                                             | 
                                                -82.20
                                                
                                             | — | 
| Diluted earnings per share |  | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.493
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.496
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.529
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                -465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                313,066,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                516,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -2,771,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                719,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -84,090,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -268,136,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -388,837,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                315,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                402,831,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                486,371,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |