Key Financial Data Of Reporting Company
| Concept | As at 2023-09-30 | 2023-07-01 to 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-09-30 | 2022-07-01 to 2022-09-30 | 2022-04-01 to 2022-09-30 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||
| Business results of reporting company | ||||||||
| Net sales | — | — | 
                                                11,633,021,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                27,164,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,185,260,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | — | 
                                                831,794,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,898,253,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                440,421,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                16,852,340,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,443,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,514,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | 
                                                26,330,008,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                29,115,187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,856,055,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | 
                                                46.00
                                                
                                             | 
                                                60.70
                                                
                                             | — | 
                                                139.57
                                                
                                             | — | 
                                                21.98
                                                
                                             | 
                                                33.26
                                                
                                             | 
| Diluted earnings per share | — | — |  | — |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.640
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.565
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.650
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                1,137,322,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,321,478,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                910,988,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -652,217,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -802,870,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -638,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -149,273,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -446,033,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -275,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                8,376,296,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,022,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,958,141,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — |