Key Financial Data Of Group
| Concept | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | |||||||||||||||||||||||||||||
| Business results of group | |||||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | — | — | 
                                                3,458,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,153,002,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,317,916,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,914,028,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,236,046,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,030,255,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,991,908,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,332,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,277,259,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,526,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | 
                                                221,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                398,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                296,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                678,541,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                282,444,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                785,781,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                182,233,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                546,183,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                185,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                402,979,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | — | — | 
                                                245,838,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                434,842,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                548,678,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                327,141,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                345,093,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | — | — | — | — | — | 
                                                385,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                569,163,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                584,623,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                354,372,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                388,882,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | — | — | — | — | — | — | 
                                                12,088,978,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,267,083,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,279,868,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,828,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                11,510,651,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,272,894,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,173,684,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,294,070,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,957,722,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,322,480,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | — | — | — | — | 
                                                18,097,132,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,464,224,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,274,385,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,340,645,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,846,209,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,381,286,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                16,208,057,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                11,202,853,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,657,689,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,219,838,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | — | — | — | — | — | 
                                                85.57
                                                
                                             | 
                                                69.95
                                                
                                             | — | — | 
                                                68.74
                                                
                                             | 
                                                84.01
                                                
                                             | — | — | — | 
                                                81.08
                                                
                                             | 
                                                67.95
                                                
                                             | 
                                                78.11
                                                
                                             | — | — | 
                                                67.45
                                                
                                             | — | 
                                                76.76
                                                
                                             | — | 
                                                67.65
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | 
                                                1.25
                                                
                                             | — | 
                                                1.82
                                                
                                             | — | — | — | 
                                                1.78
                                                
                                             | — | — | 
                                                3.20
                                                
                                             | 
                                                1.59
                                                
                                             | 
                                                3.99
                                                
                                             | — | — | — | 
                                                0.79
                                                
                                             | 
                                                2.37
                                                
                                             | — | 
                                                0.80
                                                
                                             | — | 
                                                2.50
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — |  | — |  | — | — | — |  | — | — |  |  |  | — | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | — | — | — | — | 
                                                0.636
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.808
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.823
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.654
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.657
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.815
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.664
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.830
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.676
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.831
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | 
                                                0.018
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.022
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.026
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.039
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.023
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.050
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.012
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.031
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.012
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.032
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | 
                                                70.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                48.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                37.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                20.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                46.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                100.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                33.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                66.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                21.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | 
                                                956,971,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                510,533,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                676,608,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                787,298,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                792,950,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | 
                                                -592,176,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -967,102,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                209,410,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -155,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -742,384,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | 
                                                417,893,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -197,446,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -528,039,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -49,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -370,257,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | 
                                                2,911,687,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,092,180,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,689,632,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,320,568,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,758,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Number of employees | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                46
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                90
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                455
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                97
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                386
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                96
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                447
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                444
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                425
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                96
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                451
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                68
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                54
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                191
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                59
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                118
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                52
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                192
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                191
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                180
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                52
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                180
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                54
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |