Key Financial Data Of Group
| Concept | As at 2024-12-31 | 2024-01-01 to 2024-12-31 | 2024-01-01 to 2024-12-31 | As at 2024-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | 2023-01-01 to 2023-12-31 | As at 2023-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | As at 2022-12-31 | 2022-01-01 to 2022-12-31 | 2021-01-01 to 2021-12-31 | As at 2021-12-31 | As at 2021-12-31 | 2021-01-01 to 2021-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 2020-01-01 to 2020-12-31 | As at 2020-12-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||
| Business results of group | ||||||||||||||||||||
| Net sales | — | 
                                                6,581,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,015,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,118,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                823,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                433,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | 
                                                -1,545,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -3,301,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,586,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -4,720,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,430,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | 
                                                68,055,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                65,200,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                57,544,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                58,470,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                61,504,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Total assets | 
                                                136,127,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                142,011,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                89,385,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                94,349,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                78,886,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Net assets per share | 
                                                754.41
                                                
                                             | — | — | — | — | — | — | 
                                                726.29
                                                
                                             | — | — | 
                                                699.45
                                                
                                             | — | — | 
                                                714.03
                                                
                                             | — | — | — | 
                                                754.79
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | 
                                                23.89
                                                
                                             | — | — | — | — | 
                                                -39.81
                                                
                                             | — | — | — | — | 
                                                -18.30
                                                
                                             | 
                                                -52.47
                                                
                                             | — | — | — | — | — | 
                                                -16.62
                                                
                                             | — | 
| Diluted earnings per share | — | 
                                                19.63
                                                
                                             | — | — | — | — |  | — | — | — | — |  |  | — | — | — | — | — |  | — | 
| Equity-to-asset ratio | 
                                                0.498
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                0.457
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.641
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.617
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.771
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Rate of return on equity | — | 
                                                0.0323
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | 
                                                43.87
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                58
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                374
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                350
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                41
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                202
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                32
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                198
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                23
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                190
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                1.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                62.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                69.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                2.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                2.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                12.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Revenue | — | — | 
                                                28,835,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,766,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                15,569,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                17,712,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,842,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Profit (loss) before tax | — | — | 
                                                -4,662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -10,680,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,078,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                433,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,622,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Profit (loss), attributable to owners of parent | — | — | 
                                                -4,838,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -7,193,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                382,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1,017,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Comprehensive income, attributable to owners of parent | — | — | 
                                                319,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,121,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -255,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,623,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                661,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Equity attributable to owners of parent | — | — | — | 
                                                68,518,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                66,810,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                57,936,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                57,468,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                52,381,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | 
                                                151,498,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                157,198,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                99,417,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                96,985,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                76,465,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Owners' equity per share | — | — | — | 
                                                762.15
                                                
                                             | — | 
                                                746.92
                                                
                                             | — | — | 
                                                707.20
                                                
                                             | — | — | — | — | — | 
                                                704.97
                                                
                                             | — | — | — | — | 
                                                649.92
                                                
                                             | 
| Basic earnings (loss) per share | — | — | 
                                                -53.92
                                                
                                             | — | 
                                                -87.18
                                                
                                             | — | — | — | — | 
                                                4.68
                                                
                                             | — | — | — | — | — | 
                                                12.53
                                                
                                             | 
                                                18.77
                                                
                                             | — | — | — | 
| Diluted earnings (loss) per share | — | — | 
                                                -53.92
                                                
                                             | — | 
                                                -87.18
                                                
                                             | — | — | — | — | 
                                                4.63
                                                
                                             | — | — | — | — | — | 
                                                12.40
                                                
                                             | 
                                                18.59
                                                
                                             | — | — | — | 
| Ratio of owners' equity to gross assets | — | — | — | 
                                                0.452
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.425
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.583
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.593
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.685
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | 
                                                -0.072
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                -0.115
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.007
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.019
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.030
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Price-earnings ratio | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                456.84
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                151.96
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                95.90
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Cash flows from (used in) operating activities | — | — | 
                                                -7,718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -5,273,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                9,952,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from (used in) investing activities | — | — | 
                                                -4,763,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -63,791,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,043,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                278,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -150,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash flows from (used in) financing activities | — | — | 
                                                -6,854,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                48,329,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -4,887,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                11,123,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                20,278,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | — | — | — | 
                                                32,268,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                49,065,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                66,557,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                60,087,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                40,008,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             |