Consolidated Statement Of Cash Flows
| Concept | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 2022-10-01 to 2023-09-30 | 2021-10-01 to 2022-09-30 | 2021-10-01 to 2022-09-30 | As at 2022-09-30 | As at 2021-09-30 | 
|---|---|---|---|---|---|---|---|
| Consolidated statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Profit (loss) before income taxes | — | 
                                                5,391,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,953,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,927,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,983,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Depreciation | — | — | 
                                                1,756,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,654,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in allowance for doubtful accounts | — | — | 
                                                18,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -21,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividend income | — | — | 
                                                -251,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -178,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest expenses | — | — | 
                                                38,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                38,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in retirement benefit liability | — | — | 
                                                56,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in provision for bonuses | — | — | 
                                                10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Foreign exchange losses (gains) | — | — | 
                                                155,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,345,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Subtotal | — | — | 
                                                11,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in trade receivables | — | — | 
                                                -400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,182,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Income taxes paid | — | — | 
                                                -3,498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,048,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Decrease (increase) in inventories | — | — | 
                                                2,709,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,107,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Increase (decrease) in trade payables | — | — | 
                                                43,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,766,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                7,885,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,454,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                546,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest and dividends received | — | — | 
                                                244,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                175,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Interest paid | — | — | 
                                                -34,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -41,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | — | — | 
                                                -632,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,169,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Proceeds from sale of property, plant and equipment | — | — | 
                                                1,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                14,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Purchase of investment securities | — | — | 
                                                -10,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -675,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,170,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Other, net | — | — | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from financing activities | |||||||
| Purchase of treasury shares | — | — | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                0
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Dividends paid | — | — | 
                                                -1,497,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of long-term borrowings | — | — | 
                                                -1,805,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -2,125,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -3,392,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -3,706,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Repayments of lease liabilities | — | — | 
                                                -88,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -82,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | — | 
                                                572,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,221,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | — | 
                                                4,390,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | 
                                                23,578,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                19,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,389,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |