Key Financial Data Of Reporting Company
| Concept | 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 | 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 | 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 reporting company | ||||||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||||||
| Net sales | — | — | — | 
                                                140,428,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                135,819,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                134,225,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                137,547,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                122,259,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                121,885,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                116,260,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                116,637,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | 
                                                28,643,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                26,960,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                29,673,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                29,773,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                28,922,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                26,760,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                21,372,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,442,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | 
                                                22,404,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                19,970,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                23,291,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                23,175,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                16,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Share capital | — | — | — | — | — | — | 
                                                5,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,174,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | — | — | 
                                                70,251,484
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                70,251,484
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                70,251,484
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                70,251,484
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                70,251,484
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | — | — | — | — | 
                                                207,620,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                186,746,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                176,767,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                174,378,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                162,543,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                158,682,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                145,760,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                139,721,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | 
                                                243,340,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                221,471,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                210,052,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                205,868,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                197,028,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                192,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                175,017,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                165,293,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | — | 
                                                3,082.58
                                                
                                             | — | — | — | 
                                                2,772.66
                                                
                                             | — | — | — | 
                                                2,620.02
                                                
                                             | 
                                                2,589.02
                                                
                                             | 
                                                2,409.01
                                                
                                             | — | — | 
                                                2,355.98
                                                
                                             | — | 
                                                2,160.11
                                                
                                             | — | 
                                                2,074.43
                                                
                                             | 
| Dividend paid per share | — | — | — | 
                                                124.00
                                                
                                             | — | — | — | — | — | 
                                                114.00
                                                
                                             | — | — | 
                                                110.00
                                                
                                             | — | — | — | — | 
                                                99.00
                                                
                                             | — | — | 
                                                86.00
                                                
                                             | — | — | — | 
| Interim dividend paid per share | — | — | — | 
                                                62.00
                                                
                                             | — | — | — | — | — | 
                                                57.00
                                                
                                             | — | — | 
                                                51.00
                                                
                                             | — | — | — | — | 
                                                49.00
                                                
                                             | — | — | 
                                                43.00
                                                
                                             | — | — | — | 
| Basic earnings (loss) per share | — | — | — | 
                                                332.64
                                                
                                             | — | — | — | — | — | 
                                                296.50
                                                
                                             | — | — | 
                                                345.82
                                                
                                             | 
                                                342.14
                                                
                                             | — | — | — | 
                                                344.08
                                                
                                             | 
                                                307.37
                                                
                                             | — | 
                                                240.74
                                                
                                             | — | 
                                                250.42
                                                
                                             | — | 
| Diluted earnings per share | — | — | — |  | — | — | — | — | — |  | — | — |  |  | — | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | 
                                                0.853
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.843
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.840
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.847
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.824
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.826
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.831
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.845
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | 
                                                0.114
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.110
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.140
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.136
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.155
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.135
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.119
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.120
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | 
                                                13.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                19.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                24.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                24.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                23.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                26.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                35.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                33.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | 
                                                0.373
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.384
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.318
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.288
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.357
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                16,018,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                21,388,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,737,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -6,359,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -1,564,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -2,339,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                -6,801,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -6,199,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -5,660,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                60,566,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                57,883,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                44,298,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Number of employees | 
                                                261
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                170
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,782
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,213
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,865
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,587
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                97
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,857
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,186
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                2,125
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,827
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,059
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,806
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2,026
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,793
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | — | — | 
                                                0.621
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.774
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.070
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.044
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.063
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | — | — | — | — | 
                                                1.962
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.388
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.905
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |