Key Financial Data Of Reporting Company
| 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 reporting company | ||||||
| Business results of reporting company | ||||||
| Net sales | — | 
                                                6,601,487,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                12,986,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,006,883,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                548,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,075,002,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                354,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                9,307,495,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,353,925,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,077,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                13,002,453,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                13,796,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,174,443,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                28.72
                                                
                                             | 
                                                52.76
                                                
                                             | — | — | 
                                                16.12
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.716
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.678
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.689
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                381,608,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,175,327,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                606,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -642,120,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -754,721,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -131,262,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -523,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -806,059,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -464,127,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                3,073,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,848,921,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,243,955,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |