Key Financial Data Of Group
| Concept | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | As at 2024-09-30 | 2023-10-01 to 2024-09-30 | As at 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 group | |||||||||||||||||||||||||
| Business results of group | |||||||||||||||||||||||||
| Net sales | — | 
                                                7,043,351,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,462,203,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,349,156,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,757,306,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,093,241,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,268,412,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,155,032,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,172,330,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,823,150,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,996,588,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                -1,775,401,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,712,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                430,368,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                412,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                186,071,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                171,635,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                30,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,836,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                183,212,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                204,472,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | 
                                                -1,954,414,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                205,448,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                85,716,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -73,887,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                168,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Comprehensive income | — | — | — | — | — | — | — | 
                                                -1,952,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                206,317,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                86,968,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -73,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                168,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets | 
                                                352,470,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                313,107,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,243,295,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,258,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,966,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,993,279,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,850,074,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,822,953,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,996,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,996,805,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                2,782,507,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,770,569,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,926,253,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,101,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,568,563,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,617,776,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,235,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,219,136,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,375,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,375,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share | 
                                                50.18
                                                
                                             | — | — | — | 
                                                40.39
                                                
                                             | — | — | — | — | 
                                                564.47
                                                
                                             | — | 
                                                538.76
                                                
                                             | — | — | 
                                                485.10
                                                
                                             | 
                                                491.86
                                                
                                             | — | 
                                                481.04
                                                
                                             | — | 
                                                473.87
                                                
                                             | — | — | 
                                                527.84
                                                
                                             | 
                                                527.84
                                                
                                             | — | 
| Basic earnings (loss) per share | — | 
                                                -494.31
                                                
                                             | — | — | — | — | — | 
                                                -488.27
                                                
                                             | — | — | 
                                                54.91
                                                
                                             | — | 
                                                52.06
                                                
                                             | 
                                                8.32
                                                
                                             | — | — | 
                                                22.16
                                                
                                             | — | 
                                                -12.37
                                                
                                             | — | 
                                                -19.54
                                                
                                             | 
                                                97.82
                                                
                                             | — | — | 
                                                45.72
                                                
                                             | 
| Diluted earnings per share | — |  | — | — | — | — | — |  | — | — | 
                                                53.88
                                                
                                             | — | 
                                                51.09
                                                
                                             | 
                                                8.05
                                                
                                             | — | — | 
                                                21.44
                                                
                                             | — |  | — |  | 
                                                89.24
                                                
                                             | — | — | 
                                                41.71
                                                
                                             | 
| Equity-to-asset ratio | 
                                                0.0726
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.0587
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.4316
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.4197
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.7372
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.7335
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.8143
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.8082
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.8405
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.8405
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.1078
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.1012
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0173
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0462
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.2033
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0901
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                33.75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                35.59
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                148.32
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                55.69
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                36.39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                77.87
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | 
                                                -933,675,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -70,504,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                225,903,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -73,169,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                142,126,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | 
                                                -652,226,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -470,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -156,913,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -118,725,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -102,495,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | 
                                                748,908,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                452,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                68,752,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -130,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                90,038,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                528,651,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1,365,645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,453,932,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,316,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,638,701,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                205
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                117
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                161
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                154
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                145
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                186
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                128
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                118
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                155
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                126
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                126
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Average number of temporary employees | 
                                                21
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |