Consolidated Statement Of Cash Flows
| Concept | As at 2023-09-30 | 2023-04-01 to 2023-09-30 | As at 2023-03-31 | As at 2022-09-30 | 2022-04-01 to 2022-09-30 | As at 2022-03-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Profit (loss) before income taxes | — | 
                                                133,339,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                327,318,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | 
                                                153,636,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                154,818,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Amortization of goodwill | — | 
                                                9,350,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,350,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in allowance for doubtful accounts | — | 
                                                -1,050,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -733,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividend income | — | 
                                                -28,066,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -28,015,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest expenses | — | 
                                                5,046,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in provision for bonuses | — | 
                                                35,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                85,827,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in retirement benefit liability | — | 
                                                -22,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Foreign exchange losses (gains) | — | 
                                                -17,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -46,120,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Subtotal | — | 
                                                281,990,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                568,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Decrease (increase) in trade receivables | — | 
                                                -676,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                116,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Decrease (increase) in inventories | — | 
                                                121,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -118,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in trade payables | — | 
                                                438,762,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                111,786,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                250,178,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                664,764,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                109,091,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -146,663,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                28,068,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                28,090,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -4,957,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -5,799,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | — | 
                                                -87,586,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -152,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -227,379,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -132,966,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Purchase of investment securities | — | 
                                                -10,953,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -919,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                -7,407,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | ||||||
| Proceeds from long-term borrowings | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                70,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in short-term borrowings | — | 
                                                -400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | — | 
                                                -112,249,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -112,436,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of long-term borrowings | — | 
                                                -14,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -124,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Redemption of bonds | — | 
                                                -108,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -98,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -669,590,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -304,380,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of lease liabilities | — | 
                                                -34,491,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -39,093,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Other, net | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                25,440,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                50,457,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -621,352,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                277,874,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                3,311,162,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,932,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,303,906,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,026,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |