Key Financial Data Of Reporting Company
| Concept | As at 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 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 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 reporting company | |||||||||||||||||||||||||||
| Business results of reporting company | |||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | 
                                                113,939,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                104,840,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                96,235,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                105,824,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                96,149,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                105,709,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                91,191,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                101,027,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                91,755,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                101,257,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | 
                                                9,348,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                8,583,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,361,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,412,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,008,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,342,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,972,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,598,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                8,225,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,734,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | — | — | — | — | — | — | — | 
                                                6,010,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,210,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,709,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,906,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,674,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | — | — | — | — | — | — | 
                                                4,993,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,993,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,993,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,993,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,993,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | — | — | — | — | 
                                                37,375,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                37,375,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                37,375,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                37,375,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                37,375,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | — | — | 
                                                89,239,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                82,001,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                84,284,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                77,279,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                73,673,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                79,704,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                76,712,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                70,730,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                74,767,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                69,126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | 
                                                102,066,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                93,481,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                102,701,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                93,968,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                90,390,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                98,188,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                94,371,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                86,884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                94,028,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                86,336,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | 
                                                2,495.53
                                                
                                             | — | — | — | 
                                                2,332.46
                                                
                                             | — | — | — | — | 
                                                2,410.12
                                                
                                             | 
                                                2,254.48
                                                
                                             | — | 
                                                2,153.95
                                                
                                             | 
                                                2,283.42
                                                
                                             | — | — | — | 
                                                2,177.99
                                                
                                             | 
                                                2,046.20
                                                
                                             | 
                                                2,086.85
                                                
                                             | — | — | 
                                                1,967.11
                                                
                                             | 
| Dividend paid per share | — | — | — | — | — | — | — | — | — | — | 
                                                85.0
                                                
                                             | 
                                                75.0
                                                
                                             | — | — | — | 
                                                65.0
                                                
                                             | — | — | — | 
                                                60.0
                                                
                                             | — | — | — | — | 
                                                55.0
                                                
                                             | — | — | 
| Interim dividend paid per share | — | — | — | — | — | — | — | — | — | — | 
                                                40.0
                                                
                                             | 
                                                35.0
                                                
                                             | — | — | — | 
                                                30.0
                                                
                                             | — | — | — | 
                                                30.0
                                                
                                             | — | — | — | — | 
                                                25.0
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | — | — | — | — | 
                                                185.25
                                                
                                             | — | — | — | — | 
                                                173.72
                                                
                                             | 
                                                152.61
                                                
                                             | 
                                                169.42
                                                
                                             | — | — | 
                                                166.92
                                                
                                             | — | — | 
                                                164.34
                                                
                                             | 
                                                140.09
                                                
                                             | 
                                                146.55
                                                
                                             | — | — | — | 
                                                160.69
                                                
                                             | 
                                                186.58
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | 
                                                183.35
                                                
                                             | — | — | — | — | 
                                                171.94
                                                
                                             | 
                                                150.71
                                                
                                             | 
                                                167.31
                                                
                                             | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | — | — | 
                                                0.858
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.875
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.801
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.819
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.814
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.794
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.798
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.814
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.780
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.801
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | 
                                                0.075
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.076
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.069
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.072
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.073
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.070
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.069
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.084
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.092
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | 
                                                11.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                12.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                13.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                11.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | — | — | — | — | — | — | — | 
                                                0.4893
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.4915
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.3894
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.4283
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.3423
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | 
                                                7,468,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                5,377,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                7,121,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,007,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                8,855,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | 
                                                -8,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -1,309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -304,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,032,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -483,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | 
                                                -8,124,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | 
                                                -2,726,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,860,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,424,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,884,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | 
                                                44,817,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | 
                                                54,187,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                52,639,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                48,581,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                47,870,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                327
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                251
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                251
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                281
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,270
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                411
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                804
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                281
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,365
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                820
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                825
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,387
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,478
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                817
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,486
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                842
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                17
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                73
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                488
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                386
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                73
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                460
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                83
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                517
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                598
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                111
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                598
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                121
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | — | — | — | — | 
                                                1.974
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.845
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.655
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.261
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.505
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | — | — | — | — | — | — | 
                                                2.134
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2.168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.534
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.450
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.421
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |