Quarterly Consolidated 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 consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Subtotal | 
                                                914,602,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                395,193,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -68,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -66,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -237,354,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -175,547,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                677,420,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                219,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | 
                                                -4,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -14,820,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -86,545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -19,411,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from issuance of shares | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of treasury shares | 
                                                -115,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -180,407,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -98,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -187,872,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -103,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                403,002,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                96,713,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                3,061,580,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,658,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,185,847,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,001,899,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |