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 | 
                                                -1,292,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -583,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                76,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -5,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,158,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -1,605,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,593,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -1,299,118,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -586,821,000
                                                
                                                    
                                                        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 | 
                                                -9,025,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -12,026,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Net cash provided by (used in) investing activities | 
                                                -10,005,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -15,254,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from issuance of bonds | 
                                                660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from long-term borrowings | 
                                                226,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                166,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                567,628,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                134,466,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Redemption of bonds | 
                                                -357,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -9,524,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -741,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -467,404,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                266,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                1,126,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,867,264,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,334,668,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |