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 | — | 
                                                16,955,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                31,279,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,304,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                2,065,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,017,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,275,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                12,678,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                13,289,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,732,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                17,560,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                17,918,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,791,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                26.37
                                                
                                             | 
                                                39.39
                                                
                                             | — | — | 
                                                16.57
                                                
                                             | 
| Diluted earnings per share | — | 
                                                26.11
                                                
                                             | 
                                                38.95
                                                
                                             | — | — | 
                                                16.42
                                                
                                             | 
| Equity-to-asset ratio | 
                                                0.7064
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.7237
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.6511
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                1,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,299,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,296,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -95,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,078,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -91,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -1,922,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,771,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,108,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                9,458,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,904,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |