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 | 
                                                659,194,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,778,239,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,776,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                572,875,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | — | 
                                                690,325,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                716,238,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Impairment losses | — | — | 
                                                29,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                154,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in allowance for doubtful accounts | — | — | 
                                                73,969,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                101,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -14,460,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -13,760,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                34,449,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,879,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in retirement benefit liability | — | — | 
                                                -11,391,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -25,415,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in provision for bonuses | — | — | 
                                                560,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,132,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                2,176,468,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,665,327,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in trade receivables | — | — | 
                                                8,380,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -147,546,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                -610,458,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,011,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -711,771,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -291,951,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                -24,428,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -233,680,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                1,485,125,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,588,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -74,079,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                320,986,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Loss (gain) on sale of non-current assets | — | — | 
                                                -136,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                530,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                5,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,973,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -34,511,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -26,657,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -491,327,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -583,841,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of property, plant and equipment | — | — | 
                                                2,303,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,668,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -492,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -583,063,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                -226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from collection of loans receivable | — | — | 
                                                681,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -884,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,781,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | — | — | 
                                                -132,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from long-term borrowings | — | — | 
                                                680,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in short-term borrowings | — | — | 
                                                -780,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -232,074,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -174,141,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of long-term borrowings | — | — | 
                                                -685,797,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -792,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -1,037,119,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,491,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                -44,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -485,927,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | 
                                                1,369,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,413,649,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,899,577,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |