Key Financial Data Of Reporting Company
| Concept | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2023-09-30 | 2022-10-01 to 2023-09-30 | 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 2022-09-30 | 2021-10-01 to 2022-09-30 | As at 2021-09-30 | 2020-10-01 to 2021-09-30 | As at 2021-09-30 | 2020-10-01 to 2021-09-30 | 2019-10-01 to 2020-09-30 | As at 2020-09-30 | As at 2020-09-30 | 2019-10-01 to 2020-09-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||
| Net sales | — | 
                                                1,563,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,969,509,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,975,323,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,301,389,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,301,389,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,435,592,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,979,825,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                -865,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -689,685,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -709,554,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -319,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -359,295,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -413,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -583,378,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) | — | 
                                                -889,625,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -659,130,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -482,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -512,634,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -777,021,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | 
                                                -6,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -46,726,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -19,069,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Share capital | — | — | 
                                                2,777,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,777,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,777,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,624,632,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,992,531,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total number of issued shares | — | — | 
                                                10,803,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                10,803,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                10,803,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                10,303,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                8,303,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
| Net assets | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                735,537,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,648,559,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,653,572,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,307,690,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,297,065,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,460,297,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,709,388,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,569,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,667,906,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,673,754,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                3,064,855,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,056,566,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,765,244,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,073,338,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share |  | — | 
                                                68.56
                                                
                                             | — | 
                                                151.44
                                                
                                             | — | 
                                                151.90
                                                
                                             | — | — | 
                                                212.87
                                                
                                             | 
                                                211.88
                                                
                                             | — | 
                                                240.52
                                                
                                             | — |  | — | — | 
                                                207.65
                                                
                                             |  | — | 
| Dividend paid per share | — |  | — | — | — |  | — | — |  | — | — | — | — |  | — | — |  | — | — | — | 
| Interim dividend paid per share | — |  | — | — | — |  | — | — |  | — | — | — | — |  | — | — |  | — | — | — | 
| Basic earnings (loss) per share | — | 
                                                -82.92
                                                
                                             | — |  | — | 
                                                -61.43
                                                
                                             | — | 
                                                -59.98
                                                
                                             | 
                                                -47.09
                                                
                                             | — | — | 
                                                -48.12
                                                
                                             | — | 
                                                -56.43
                                                
                                             | — |  | 
                                                -105.42
                                                
                                             | — | — |  | 
| Diluted earnings per share | — |  | — |  | — |  | — |  |  | — | — |  | — |  | — |  |  | — | — |  | 
| Equity-to-asset ratio | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.469
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.609
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.610
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.745
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.744
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.890
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.824
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | — | 
                                                -0.754
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -0.311
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -0.304
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                -0.196
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                -0.217
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -0.246
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                -0.461
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Payout ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                -207,224,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                39,113,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -318,284,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -521,091,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                157,404,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -25,164,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                247,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -984,280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -19,447,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                33,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                -36,850,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -91,019,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                297,713,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,230,659,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -500,818,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                553,823,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                825,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                630,402,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,635,254,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                945,134,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                43
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                51
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                51
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                50
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                50
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Average number of temporary employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Total shareholder return | — | — | 
                                                0.404
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.297
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.561
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.820
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.959
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Total return on share price index | — | — | 
                                                1.879
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.612
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.242
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.337
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.049
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — |