Quarterly Consolidated Statement Of Cash Flows
| Concept | As at 2024-09-30 | 2024-04-01 to 2024-09-30 | As at 2024-03-31 | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | — | 
                                                537,060,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                419,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                11,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -25,950,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -21,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | — | 
                                                -289,755,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -141,817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                232,979,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                266,476,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | — | 
                                                -257,732,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -73,002,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | — | 
                                                -2,089,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -2,369,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                58,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -287,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -302,836,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -123,413,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | ||||||
| Repayments of long-term borrowings | — | 
                                                -30,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -45,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | — | 
                                                -74,776,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -61,580,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -397,525,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -426,693,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -467,382,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -283,631,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                2,471,103,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,938,485,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,325,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,609,558,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |