Consolidated Statement Of Cash Flows
| Concept | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 
|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | 
                                                391,253,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                413,539,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                5,592,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -314,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -187,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -98,668,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -39,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                329,332,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                378,639,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -18,387,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -565,610,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -22,666,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -501,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -4,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -4,730,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | 
                                                -66,837,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -63,492,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -48,594,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -50,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid to non-controlling interests | 
                                                -750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -116,181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -113,576,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                190,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -236,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                1,170,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                979,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,215,883,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |