Quarterly Statement Of Cash Flows
| Concept | As at 2023-12-31 | 2023-07-01 to 2023-12-31 | As at 2023-06-30 | 2022-07-01 to 2022-12-31 | As at 2022-12-31 | As at 2022-06-30 | 
|---|---|---|---|---|---|---|
| Quarterly statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Profit (loss) before income taxes | — | 
                                                320,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                358,297,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Depreciation | — | 
                                                76,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                84,668,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividend income | — | 
                                                -1,143,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest expenses | — | 
                                                3,555,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,883,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Decrease (increase) in trade receivables | — | 
                                                -2,006,787,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,954,943,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Increase (decrease) in trade payables | — | 
                                                120,469,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                152,263,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                -337,440,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -340,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Subtotal | — | 
                                                -1,666,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,474,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | — | 
                                                1,143,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,256,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | — | 
                                                -3,974,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -5,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | — | 
                                                -255,913,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -319,053,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -1,911,494,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,747,894,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Purchase of property, plant and equipment | — | 
                                                -135,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -100,970,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                15,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                181,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of investment securities | — | 
                                                -10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Loan advances | — | 
                                                -20,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                8,341,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,713,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -64,494,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -84,674,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from long-term borrowings | — | 
                                                159,970,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of treasury shares | — | 
                                                -159,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,053,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | — | 
                                                -155,183,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -130,234,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                1,803,261,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,268,166,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                -11,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -18,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                -172,738,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -564,421,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                1,457,720,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,630,459,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,393,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,957,868,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |