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 | 
                                                307,649,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                193,065,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                97,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                44,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -126,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -193,698,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -19,135,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -13,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                129,132,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -45,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from operating activities | |||||
| Cash flows from operating activities | |||||
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -1,959,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -5,712,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                1,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -99,899,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                71,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                193,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of investment securities | 
                                                108,201,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                600,312,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from facilities maintenance and investing activities | |||||
| Cash flows from financing activities | |||||
| Proceeds from long-term borrowings | 
                                                49,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                225,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -868,242,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                355,912,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -411,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -343,762,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                2,785,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                255,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -664,879,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                504,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                771,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,436,023,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                898,182,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |