Key Financial Data Of Group
| Concept | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 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 | 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 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||||||||||
| Net sales | — | — | 
                                                54,411,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,023,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                25,715,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                53,425,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                24,770,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                48,515,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                22,806,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                42,337,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                20,962,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                35,588,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | 
                                                7,139,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,160,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,891,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,986,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,043,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                3,666,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,572,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,965,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,253,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | 
                                                4,276,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                4,931,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                4,381,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,541,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                2,623,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | 
                                                6,627,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                8,169,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                7,064,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,900,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,223,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | 
                                                53,561,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                35,061,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                50,074,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                32,700,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                31,198,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                45,255,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                40,210,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,190,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                36,133,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                27,852,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | 
                                                69,202,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                42,938,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                66,144,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                40,676,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                38,806,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                60,136,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                55,818,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                37,842,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                49,458,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                35,662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | 
                                                1,190.89
                                                
                                             | — | 
                                                891.17
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                1,109.65
                                                
                                             | — | 
                                                821.71
                                                
                                             | — | — | 
                                                770.96
                                                
                                             | 
                                                989.09
                                                
                                             | — | — | — | 
                                                876.20
                                                
                                             | 
                                                717.99
                                                
                                             | 
                                                784.91
                                                
                                             | — | — | 
                                                678.03
                                                
                                             | 
| Basic earnings (loss) per share | — | — | 
                                                108.21
                                                
                                             | — | — | — | — | 
                                                137.58
                                                
                                             | — | — | — | — | 
                                                91.37
                                                
                                             | 
                                                122.13
                                                
                                             | — | — | — | — | 
                                                82.92
                                                
                                             | — | — | 
                                                108.25
                                                
                                             | 
                                                67.06
                                                
                                             | 
                                                86.32
                                                
                                             | — | — | — | 
                                                89.54
                                                
                                             | 
                                                63.34
                                                
                                             | — | 
| Diluted earnings per share | — | — |  | — | — | — | — |  | — | — | — | — |  |  | — | — | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | 
                                                0.677
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.817
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                0.668
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.804
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.804
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.666
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.638
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.771
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.652
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.781
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | 
                                                0.094
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.160
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.115
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.117
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.111
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.116
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.096
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.104
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.139
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.083
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | 
                                                10.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                8.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                14.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                12.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                9.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                11.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | 
                                                9,746,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                6,770,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                4,329,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                3,889,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,602,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | 
                                                -3,255,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                -1,260,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                -3,323,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,078,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,067,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | 
                                                -3,932,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                -3,584,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                -2,357,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -2,103,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,958,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | 
                                                17,686,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                14,608,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                12,080,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,916,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,643,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                216
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,906
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                610
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                465
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                442
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                663
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                120
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                110
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                641
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                469
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,865
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                210
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                606
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                435
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                601
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,799
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,764
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                612
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,748
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                624
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |