Consolidated Statement Of Cash Flows
| Concept | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | As at 2022-03-31 | 
|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||
| Statement of cash flows | |||||
| Cash flows from operating activities | |||||
| Profit (loss) before income taxes | — | 
                                                618,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                157,179,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | 
                                                608,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                755,557,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Impairment losses | — | 
                                                152,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                439,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in allowance for doubtful accounts | — | 
                                                3,786,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividend income | — | 
                                                -2,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in provision for retirement benefits | — | 
                                                21,923,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in provision for bonuses | — | 
                                                7,478,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -17,421,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Subtotal | — | 
                                                1,370,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,453,597,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | — | 
                                                -181,552,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -115,678,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Decrease (increase) in inventories | — | 
                                                8,320,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in trade payables | — | 
                                                -238,604,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                232,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                1,191,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,339,174,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                -6,898,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,918,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                2,131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Loss (gain) on sale of non-current assets | — | 
                                                200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | |||||
| Payments into time deposits | — | 
                                                -2,869,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,867,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from withdrawal of time deposits | — | 
                                                2,869,015,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,677,027,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of property, plant and equipment | — | 
                                                -511,085,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -619,729,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                92,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                110,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -523,035,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,010,311,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                18,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -33,281,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | — | 
                                                -50,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | — | 
                                                -283,099,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -283,074,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -286,137,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -285,944,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of lease liabilities | — | 
                                                -2,987,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                382,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -957,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                4,099,395,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,717,088,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,674,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |