Semi-Annual Consolidated Statement Of Cash Flows
| Concept | As at 2024-03-31 | 2023-10-01 to 2024-03-31 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 2021-10-01 to 2022-09-30 | As at 2022-09-30 | As at 2021-09-30 | 
|---|---|---|---|---|---|---|---|
| Semi-annual consolidated statement of cash flows | |||||||
| Statement of cash flows | |||||||
| Cash flows from operating activities | |||||||
| Subtotal | — | 
                                                286,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                324,310,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                434,200,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest and dividends received | — | 
                                                61,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                43,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                15,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Interest paid | — | 
                                                -2,669,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -5,377,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -5,713,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Income taxes paid | — | 
                                                -54,865,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -7,502,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -194,213,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                229,465,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                37,274,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                208,488,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from investing activities | |||||||
| Purchase of property, plant and equipment | — | 
                                                -25,636,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -19,645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -155,578,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Proceeds from sale of property, plant and equipment | — | 
                                                30,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                70,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                2,175,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -5,291,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,454,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -32,804,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -42,285,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -179,777,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash flows from financing activities | |||||||
| Proceeds from long-term borrowings | — | 
                                                300,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                400,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Repayments of long-term borrowings | — | 
                                                -233,174,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -640,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -524,452,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) financing activities | — | 
                                                112,925,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                351,580,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -331,419,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Other, net | — | 
                                                -3,900,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -7,515,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -6,967,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Effect of exchange rate change on cash and cash equivalents | — | 
                                                -1,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,635,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -1,049,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net increase (decrease) in cash and cash equivalents | — | 
                                                308,554,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                342,933,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -303,757,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Cash and cash equivalents | 
                                                1,287,093,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                978,538,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                635,605,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                939,363,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |