Key Financial Data Of Reporting Company
| Concept | As at 2024-04-30 | 2023-05-01 to 2024-04-30 | As at 2024-04-30 | 2023-05-01 to 2024-04-30 | As at 2023-04-30 | 2022-05-01 to 2023-04-30 | As at 2023-04-30 | 2022-05-01 to 2023-04-30 | 2021-05-01 to 2022-04-30 | As at 2022-04-30 | 2021-05-01 to 2022-04-30 | As at 2022-04-30 | 2020-05-01 to 2021-04-30 | As at 2021-04-30 | As at 2021-04-30 | 2020-05-01 to 2021-04-30 | 2019-05-01 to 2020-04-30 | 2019-05-01 to 2020-04-30 | As at 2020-04-30 | As at 2020-04-30 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||
| Net sales | — | 
                                                10,972,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,972,526,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,213,880,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,553,497,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,108,822,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,659,098,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,597,906,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                8,080,977,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,109,968,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,805,146,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | — | 
                                                1,114,768,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,149,480,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,102,678,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,244,124,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,502,011,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,549,323,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                675,702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                812,087,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                538,252,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                485,654,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Profit (loss) | — | 
                                                1,739,600,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                866,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,038,351,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                471,030,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                347,759,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | 
                                                592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                592,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total number of issued shares | — | — | 
                                                1,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                1,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                1,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                1,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                1,360,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
| Net assets | 
                                                15,546,228,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,311,353,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,241,611,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                14,456,765,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                12,358,750,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                13,334,289,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                12,246,885,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,474,209,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                10,811,808,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,394,699,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                17,903,348,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,623,691,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                15,855,780,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                17,139,298,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                15,317,309,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                16,362,407,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                14,452,110,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,627,901,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,557,817,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                13,163,195,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | 
                                                11,451.65
                                                
                                             | — | 
                                                11,278.64
                                                
                                             | — | 
                                                9,753.36
                                                
                                             | — | 
                                                10,648.40
                                                
                                             | — | — | 
                                                9,102.69
                                                
                                             | — | 
                                                9,821.21
                                                
                                             | — | 
                                                9,020.29
                                                
                                             | 
                                                8,451.19
                                                
                                             | — | — | — | 
                                                7,963.13
                                                
                                             | 
                                                8,392.44
                                                
                                             | 
| Dividend paid per share | — | 
                                                80.00
                                                
                                             | — | — | — | — | — | 
                                                80.00
                                                
                                             | 
                                                100.00
                                                
                                             | — | — | — | 
                                                80.00
                                                
                                             | — | — | — | — | 
                                                80.00
                                                
                                             | — | — | 
| Interim dividend paid per share | — |  | — | — | — | — | — |  |  | — | — | — |  | — | — | — | — |  | — | — | 
| Basic earnings (loss) per share | — | 
                                                1,281.38
                                                
                                             | — | 
                                                1,063.10
                                                
                                             | — | 
                                                804.45
                                                
                                             | — | 
                                                638.39
                                                
                                             | 
                                                764.78
                                                
                                             | — | 
                                                797.27
                                                
                                             | — | 
                                                346.92
                                                
                                             | — | — | 
                                                421.17
                                                
                                             | 
                                                300.09
                                                
                                             | 
                                                256.13
                                                
                                             | — | — | 
| Diluted earnings per share | — |  | — |  | — |  | — |  |  | — |  | — |  | — | — |  |  |  | — | — | 
| Equity-to-asset ratio | 
                                                0.868
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.869
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.835
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.843
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.807
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.815
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.847
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.842
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.861
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.866
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | 
                                                0.122
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.096
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.068
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.087
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.085
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.042
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.048
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.036
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.032
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Price-earnings ratio | — | 
                                                4.84
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5.83
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5.30
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                6.67
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5.27
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5.05
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                11.98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                9.87
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11.91
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Payout ratio | — | 
                                                0.062
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.125
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.131
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.231
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | 
                                                1,664,336,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,089,934,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                927,105,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                912,228,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,041,128,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) investing activities | — | — | — | 
                                                -2,576,061,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                422,856,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -975,574,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                324,605,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -631,568,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Net cash provided by (used in) financing activities | — | — | — | 
                                                -214,138,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -266,558,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -60,244,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -362,742,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                164,322,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Cash and cash equivalents | 
                                                5,150,833,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                6,292,801,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                5,055,620,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,082,612,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,154,280,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                287
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                286
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                283
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                287
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                279
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                315
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                310
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                277
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                273
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                307
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                22
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                18
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | 
                                                1.427
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.991
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.920
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.930
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.675
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Total return on share price index | — | — | 
                                                1.912
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.402
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.260
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.229
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.929
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |