Key Financial Data Of Group
| Concept | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | 2023-07-01 to 2023-09-30 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2022-04-01 to 2022-09-30 | As at 2022-09-30 | 2022-07-01 to 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||
| Business results of group | ||||||||
| Net sales | 
                                                2,742,061,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,020,260,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,691,646,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | 
                                                75,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                310,574,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                87,761,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets | — | 
                                                3,006,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,012,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,816,627,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | — | 
                                                5,929,443,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,062,236,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,359,525,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | 
                                                12.44
                                                
                                             | — | 
                                                2.69
                                                
                                             | — | 
                                                67.27
                                                
                                             | 
                                                15.24
                                                
                                             | — | 
                                                7.45
                                                
                                             | 
| Diluted earnings per share |  | — | — | — |  |  | — | — | 
| Equity-to-asset ratio | — | 
                                                0.507
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.497
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.526
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                207,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -213,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                228,034,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -172,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -125,427,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -89,599,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                238,795,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                384,409,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -142,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                782,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                508,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                459,329,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |