Semi-Annual 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 | 
|---|---|---|---|---|---|
| Semi-annual consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | 
                                                269,281,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                559,129,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                1,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -6,637,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -7,413,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -46,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -85,271,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                198,288,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                393,624,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -5,541,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,641,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                64,235,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -440,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of investment securities | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of shares of subsidiaries resulting in change in scope of consolidation | 
                                                -2,258,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -51,117,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -241,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                240,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -30,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,024,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Proceeds from long-term borrowings | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Redemption of bonds | 
                                                -3,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -252,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -271,755,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of treasury shares | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -33,603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -68,337,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -59,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -333,254,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -384,379,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,056,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -165,714,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,269,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                2,358,821,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,524,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,505,267,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |