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 | — | 
                                                494,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                589,359,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Depreciation | — | 
                                                22,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividend income | — | 
                                                -84,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in provision for retirement benefits | — | 
                                                -280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,980,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest expenses | — | 
                                                3,945,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,334,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Increase (decrease) in provision for bonuses | — | 
                                                37,235,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,204,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Decrease (increase) in trade receivables | — | 
                                                29,171,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -13,258,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Subtotal | — | 
                                                747,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                541,571,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Decrease (increase) in inventories | — | 
                                                2,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,023,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Income taxes paid | — | 
                                                -193,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -210,062,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                549,417,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                344,756,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest and dividends received | — | 
                                                84,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                131,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Interest paid | — | 
                                                -4,029,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -4,296,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from investing activities | |||||
| Purchase of property, plant and equipment | — | 
                                                -5,473,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -4,463,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                3,724,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                1,706,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -4,463,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Proceeds from sale of investment securities | — | 
                                                4,078,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash flows from financing activities | |||||
| Purchase of treasury shares | — | 
                                                -54,151,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in short-term borrowings | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -50,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Dividends paid | — | 
                                                -159,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -118,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                -214,645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -170,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Repayments of lease liabilities | — | 
                                                -1,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,144,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                336,479,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                170,211,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                3,755,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,419,047,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,248,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |