Key Financial Data Of Group
| Concept | As at 2024-03-31 | 2024-01-01 to 2024-03-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Key financial data of group | ||||||
| Business results of group | ||||||
| Net sales | — | 
                                                1,354,012,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,059,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,177,321,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | 
                                                42,766,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                425,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                20,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | 
                                                18,638,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                626,528,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                55,599,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | 
                                                -18,808,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                563,201,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                261,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | 
                                                4,498,270,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,677,929,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,492,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                5,827,413,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,602,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,444,832,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Basic earnings (loss) per share | — | 
                                                2.09
                                                
                                             | 
                                                70.14
                                                
                                             | — | 
                                                6.23
                                                
                                             | — | 
| Diluted earnings per share | — |  |  | — |  | — | 
| Equity-to-asset ratio | 
                                                0.772
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.835
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.825
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |