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 | 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 | — | — | — | — | — | — | — | — | 
                                                23,638,074,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                25,070,067,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                20,942,538,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                22,627,321,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,294,305,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,957,620,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                26,191,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                27,798,445,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                26,956,774,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                28,459,165,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | — | 
                                                1,570,402,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,720,894,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,117,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,396,120,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,302,250,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                2,599,708,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,087,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,395,995,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,817,221,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,049,878,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | — | — | — | 
                                                1,177,042,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                1,052,052,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,840,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,306,716,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,103,650,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | — | — | — | — | — | — | 
                                                1,427,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                843,366,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,629,742,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,790,415,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,006,545,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | — | — | — | — | — | — | — | 
                                                20,616,433,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,911,320,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                18,062,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                19,556,474,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                19,162,081,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,827,185,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,108,816,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,975,287,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,853,993,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                14,972,264,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | — | — | — | — | — | 
                                                29,618,535,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                26,830,328,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,594,371,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,191,190,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                26,208,966,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                23,787,397,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,555,879,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                24,895,132,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                24,706,598,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,377,481,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | — | — | — | — | — | — | 
                                                2,801.32
                                                
                                             | — | 
                                                2,569.63
                                                
                                             | — | 
                                                2,454.37
                                                
                                             | 
                                                2,657.30
                                                
                                             | — | — | — | 
                                                2,601.32
                                                
                                             | 
                                                2,422.32
                                                
                                             | 
                                                2,458.84
                                                
                                             | — | — | 
                                                2,306.57
                                                
                                             | — | 
                                                2,153.20
                                                
                                             | — | 
                                                2,034.35
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | — | 
                                                147.08
                                                
                                             | — | 
                                                159.93
                                                
                                             | — | — | — | 
                                                118.98
                                                
                                             | — | — | 
                                                142.95
                                                
                                             | 
                                                224.42
                                                
                                             | 
                                                250.11
                                                
                                             | — | — | — | 
                                                289.28
                                                
                                             | 
                                                313.43
                                                
                                             | — | 
                                                265.95
                                                
                                             | — | 
                                                285.83
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — | — |  | — |  | — | — | — |  | — | — |  |  |  | — | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | — | — | — | — | — | 
                                                0.696
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.705
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.766
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.747
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.730
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.749
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.681
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.682
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.641
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.640
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | — | 
                                                0.0586
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.0586
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.0488
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.0544
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0949
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0989
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.1333
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.1359
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.1377
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.1400
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | — | 
                                                10.19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                9.37
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                10.82
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                9.00
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8.11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.28
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                7.26
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6.70
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                6.32
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5.88
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | — | 
                                                3,514,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                3,750,435,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,044,293,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                583,966,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                951,588,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | — | 
                                                -263,904,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -958,119,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,020,835,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -465,914,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                103,728,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | — | 
                                                -371,544,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -520,896,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -693,595,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -612,157,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -670,728,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | — | 
                                                5,359,860,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,989,929,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                3,726,359,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,382,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,875,791,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Number of employees | 
                                                82
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                99
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                80
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                92
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                82
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                211
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                230
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                293
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                288
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                304
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                293
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                271
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                263
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                282
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                261
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |