Key Financial Data Of Reporting Company
| Concept | As at 2023-12-31 | 2023-10-01 to 2023-12-31 | 2023-07-01 to 2023-12-31 | As at 2023-06-30 | 2022-07-01 to 2023-06-30 | 2022-07-01 to 2022-12-31 | As at 2022-12-31 | 2022-10-01 to 2022-12-31 | 
|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||
| Business results of reporting company | ||||||||
| Net sales | — | — | 
                                                3,756,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,566,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,852,902,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | — | — | 
                                                228,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,202,038,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                358,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets | 
                                                6,956,741,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,862,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                6,260,211,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                10,990,218,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,021,979,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,486,636,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                22.61
                                                
                                             | 
                                                29.18
                                                
                                             | — | 
                                                127.87
                                                
                                             | 
                                                43.37
                                                
                                             | — | 
                                                24.17
                                                
                                             | 
| Diluted earnings per share | — | — |  | — |  |  | — | — | 
| Equity-to-asset ratio | 
                                                0.633
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.761
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.597
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                -1,911,494,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                619,523,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,747,894,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -64,494,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -161,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -84,674,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                1,803,261,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -785,280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,268,166,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                1,457,720,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,630,459,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,393,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — |