Key Financial Data Of Group
| Concept | 2024-01-01 to 2024-06-30 | As at 2024-06-30 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-06-30 | As at 2023-06-30 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | 
                                                2,794,401,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,059,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,404,112,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | 
                                                123,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                425,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                78,737,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | 
                                                60,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                626,528,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                177,938,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | 
                                                13,104,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                563,201,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                406,770,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                4,539,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,677,929,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,646,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                5,828,160,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,602,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,589,813,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | 
                                                6.75
                                                
                                             | — | 
                                                70.14
                                                
                                             | — | 
                                                19.93
                                                
                                             | — | 
| Diluted earnings per share |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | 
                                                0.779
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.835
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.831
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | 
                                                110,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                465,720,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                323,891,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -152,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                303,143,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                170,955,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                339,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -325,340,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -180,140,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                1,864,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,502,405,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,377,436,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |