Quarterly Statement Of Cash Flows
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Quarterly statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                -150,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -43,338,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                603,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -17,756,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -12,136,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                -163,037,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -88,217,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -50,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -22,580,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                3,181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                353,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | 
                                                -3,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,432,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -68,532,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Repayments of long-term borrowings | 
                                                -11,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from issuance of shares | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -23,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -123,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -355,516,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                199,324,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                2,181,477,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,536,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,518,517,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,319,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |