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 | 
|---|---|---|---|---|---|
| Statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Subtotal | — | 
                                                2,022,729,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,600,090,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | — | 
                                                91,292,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                61,619,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | — | 
                                                -976,365,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -677,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | — | 
                                                -7,244,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -6,075,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Compensation paid for damage | — | 
                                                -1,747,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,909,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                1,128,664,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,976,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from operating activities | |||||
| Cash flows from operating activities | |||||
| Cash flows from facilities maintenance and investing activities | |||||
| Purchase of property, plant and equipment | — | 
                                                -433,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -96,729,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | — | 
                                                -951,683,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,275,687,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||
| Net cash provided by (used in) investing activities | — | 
                                                -839,994,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,091,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||
| Proceeds from short-term borrowings | — | 
                                                650,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of short-term borrowings | — | 
                                                -1,150,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | — | 
                                                -594,070,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -401,827,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from issuance of bonds | — | 
                                                50,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -1,105,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -486,814,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -769,953,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                411,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                47,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                7,663,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,433,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,022,014,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |