Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-10-01 to 2025-03-31 | As at 2025-03-31 | As at 2024-09-30 | 2023-10-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-09-30 | 
|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                778,016,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                703,851,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -4,106,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -3,530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                801,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                665,602,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -5,952,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -4,028,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -17,399,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -40,762,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from long-term borrowings | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                300,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -99,799,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -16,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -72,340,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -71,793,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -372,140,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -472,795,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                -4,950,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                406,665,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                153,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                1,125,736,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                719,071,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,029,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                876,207,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |