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 | 
                                                482,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                391,381,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                9,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,755,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -205,635,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -66,689,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -2,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,922,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                321,772,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                465,720,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -65,173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -28,727,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                150,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -395,355,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                303,143,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -19,550,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of investment securities | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                284,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Loan advances | 
                                                -500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from collection of loans receivable | 
                                                657,318,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                180,336,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Proceeds from short-term borrowings | 
                                                500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of short-term borrowings | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -39,740,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -286,085,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -285,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                213,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -325,340,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                56,960,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                33,705,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                197,291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                477,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                1,699,697,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,502,405,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,025,175,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |