Consolidated Statement Of Cash Flows
| Concept | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | — | 
                                                4,624,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,696,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | — | 
                                                21,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | — | 
                                                -6,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | — | 
                                                -309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -77,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                4,371,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,628,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | — | 
                                                -1,400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,132,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -1,418,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,142,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                -11,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Dividends paid | — | 
                                                -258,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -258,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | — | 
                                                -620,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -620,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -997,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,390,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                53,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                2,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                119,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                2,982,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                972,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                853,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |