Consolidated 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 | 
|---|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | 
                                                4,680,167,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,161,736,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,799,926,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,060,980,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | — | 
                                                2,406,193,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,238,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in allowance for doubtful accounts | — | — | 
                                                37,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,498,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -88,278,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -54,508,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                133,815,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                124,624,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in retirement benefit liability | — | — | 
                                                -20,870,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -39,521,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in provision for bonuses | — | — | 
                                                -59,331,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                179,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Foreign exchange losses (gains) | — | — | 
                                                -74,522,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                7,926,813,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,608,952,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in trade receivables | — | — | 
                                                721,443,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -681,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                -216,219,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                702,231,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -2,052,572,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,170,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                5,925,608,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,397,331,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                -1,062,817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                366,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -316,654,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                836,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                88,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                56,614,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -132,387,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -138,530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -1,491,149,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,262,456,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of property, plant and equipment | — | — | 
                                                887,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,155,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -1,946,557,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,424,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                -50,001,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of investment securities | — | — | 
                                                1,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                359,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | — | — | 
                                                -240,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -173,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from long-term borrowings | — | — | 
                                                85,319,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,489,410,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in short-term borrowings | — | — | 
                                                340,147,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -202,287,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -785,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -702,215,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of long-term borrowings | — | — | 
                                                -973,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,647,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -1,352,336,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,079,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -19,135,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -16,950,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | — | 
                                                210,383,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                170,172,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                2,837,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,063,008,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | 
                                                15,913,644,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                13,076,546,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,013,538,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |