Consolidated Statement Of Cash Flows
| Concept | 2024-04-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-03-31 | 2023-04-01 to 2023-09-30 | As at 2023-09-30 | As at 2023-03-31 | 
|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | ||||||
| Statement of cash flows | ||||||
| Cash flows from operating activities | ||||||
| Profit (loss) before income taxes | 
                                                26,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                75,536,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Depreciation | 
                                                75,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                67,437,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Increase (decrease) in allowance for doubtful accounts | 
                                                879,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -255,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividend income | 
                                                -1,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Increase (decrease) in provision for retirement benefits | 
                                                -7,879,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                18,437,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest expenses | 
                                                2,393,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,117,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Increase (decrease) in provision for bonuses | 
                                                13,379,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Decrease (increase) in trade receivables | 
                                                503,388,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                355,197,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Subtotal | 
                                                351,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                228,650,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | 
                                                -25,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -39,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Decrease (increase) in inventories | 
                                                -47,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -19,543,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Increase (decrease) in trade payables | 
                                                -82,673,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -189,601,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | 
                                                325,592,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                207,500,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Loss (gain) on sale of non-current assets | 
                                                -672,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | 
                                                1,188,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | 
                                                -1,954,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -1,039,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | ||||||
| Payments into time deposits | 
                                                -49,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -39,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from withdrawal of time deposits | 
                                                39,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                39,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Purchase of property, plant and equipment | 
                                                -73,103,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -122,278,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | 
                                                672,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | 
                                                -103,070,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -172,300,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Loan advances | 
                                                -290,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from collection of loans receivable | 
                                                817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | ||||||
| Proceeds from long-term borrowings | 
                                                500,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                800,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in short-term borrowings | 
                                                -450,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -380,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Dividends paid | 
                                                -59,464,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -60,556,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | 
                                                -239,027,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -120,648,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | 
                                                -248,491,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                238,795,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | 
                                                -25,968,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                273,996,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | — | 
                                                452,628,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                478,597,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                782,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                508,084,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |