Statement Of Cash Flows
| Concept | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|---|---|
| Statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | — | 
                                                1,064,649,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,000,502,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,773,890,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,969,044,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | — | 
                                                1,888,068,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,903,980,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in allowance for doubtful accounts | — | — | 
                                                9,419,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -38,915,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -46,037,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                20,346,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,522,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Foreign exchange losses (gains) | — | — | 
                                                41,125,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -33,625,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in provision for bonuses | — | — | 
                                                -103,684,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -33,221,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in trade receivables | — | — | 
                                                -125,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,019,862,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                -34,122,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,369,482,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                -1,380,773,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,433,622,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                2,687,775,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,064,442,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                533,920,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,369,366,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -658,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,155,726,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                2,090,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,973,534,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                37,116,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                45,812,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -28,426,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -52,946,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from operating activities | |||||||
| Loss (gain) on sale of investment securities | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -57,480,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from operating activities | |||||||
| Cash flows from facilities maintenance and investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -3,568,077,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,683,110,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of property, plant and equipment | — | — | 
                                                5,897,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                735,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                -30,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -34,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of investment securities | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                328,154,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                63,691,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -5,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Net cash provided by (used in) investing activities | — | — | 
                                                -3,604,086,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,442,985,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -68,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from long-term borrowings | — | — | 
                                                796,681,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,530,376,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -618,978,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -617,195,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of long-term borrowings | — | — | 
                                                -95,450,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -120,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                87,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                783,218,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                -9,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -9,893,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | — | 
                                                236,850,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                289,489,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                -1,189,948,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,603,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | 
                                                10,013,538,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                11,203,486,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,600,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |