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 | — | 
                                                16,891,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                34,497,568,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,807,712,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                939,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,124,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                916,519,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                54,875,774,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                55,337,828,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                53,262,889,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                73,258,718,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                73,605,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                71,628,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                9.85
                                                
                                             | 
                                                26.19
                                                
                                             | — | — | 
                                                10.22
                                                
                                             | 
| Diluted earnings per share | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.700
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.704
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.695
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                1,804,505,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,007,843,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                946,385,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -564,880,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -873,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -574,523,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -1,204,746,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,341,768,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,445,379,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                8,697,326,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,655,846,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,721,381,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |