Quarterly Consolidated Statement Of Cash Flows
| Concept | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|
| Quarterly consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | 
                                                1,092,724,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                336,574,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | 
                                                4,150,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,534,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | 
                                                -389,109,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -92,991,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | 
                                                715,573,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                264,004,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | 
                                                -298,863,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -74,620,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of property, plant and equipment | 
                                                3,643,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | 
                                                -6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -13,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | 
                                                -466,607,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -189,615,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | 
                                                -73,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -141,704,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | 
                                                -104,894,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -106,308,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | 
                                                -165,852,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -234,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Effect of exchange rate change on cash and cash equivalents | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                83,114,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -160,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                1,922,697,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,839,582,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,000,052,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |