Quarterly 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 | 
|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                -787,120,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -140,022,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -2,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,073,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -1,594,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,592,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -790,794,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -142,683,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -8,487,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,428,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -9,587,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,744,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from long-term borrowings | 
                                                170,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                31,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -60,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from issuance of bonds | 
                                                660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of treasury shares | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                233,862,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                46,606,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                314,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -566,205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -99,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                1,301,058,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,867,264,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,235,105,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,334,668,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |