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 | 
|---|---|---|---|---|---|
| Statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | 
                                                -1,367,545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,640,892,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -2,841,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -1,374,806,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,677,464,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from operating activities | |||||
| Cash flows from operating activities | |||||
| Cash flows from facilities maintenance and investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -13,060,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -11,530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                154,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Net cash provided by (used in) investing activities | 
                                                -13,060,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -11,376,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Repayments of long-term borrowings | 
                                                -120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -119,988,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Redemption of bonds | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -32,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                567,441,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,182,027,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -7,557,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -9,290,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                39,809,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,865,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -780,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -489,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                2,108,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,889,101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,379,048,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |