Consolidated Statement Of Cash Flows
| Concept | 2024-01-01 to 2024-06-30 | As at 2024-06-30 | As at 2023-12-31 | 2023-01-01 to 2023-06-30 | As at 2023-06-30 | As at 2022-12-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                1,447,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,651,301,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                21,087,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,834,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -90,802,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -379,049,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -28,036,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -23,948,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                1,349,416,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,259,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -2,381,510,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -318,231,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                456,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,502,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                -1,148,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -2,404,832,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -325,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -2,026,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,806,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Purchase of treasury shares | 
                                                -52,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from long-term borrowings | 
                                                894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -494,671,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -604,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -329,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -374,219,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                1,870,581,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -974,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                194,502,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                98,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                1,009,668,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                58,025,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                5,031,858,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,022,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,291,825,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,233,799,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |