Statement Of Cash Flows
| Concept | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|---|
| Statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | 
                                                2,877,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,514,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,685,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,032,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | — | 
                                                2,864,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,902,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -366,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                128,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                86,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in trade receivables | — | — | 
                                                120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -776,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                -235,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,088,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                5,718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,887,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                -148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -748,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -903,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,112,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -54,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -155,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                5,056,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,978,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                366,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                290,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -86,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from operating activities | |||||||
| Loss (gain) on sale of non-current assets | — | — | 
                                                16,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -48,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from operating activities | |||||||
| Loss (gain) on sale of investment securities | — | — | 
                                                -27,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -25,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from facilities maintenance and investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -7,334,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,617,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of property, plant and equipment | — | — | 
                                                103,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                -7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -7,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of investment securities | — | — | 
                                                97,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                31,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -588,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Net cash provided by (used in) investing activities | — | — | 
                                                -7,077,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,949,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | — | — | 
                                                -314,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -252,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -875,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -832,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from long-term borrowings | — | — | 
                                                6,500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,155,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                1,678,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,453,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of long-term borrowings | — | — | 
                                                -3,484,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -31,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                -215,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,647,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | — | 
                                                126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                163,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | 
                                                14,013,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                14,229,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,582,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |