Key Financial Data Of Group
| Concept | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 2019-04-01 to 2020-03-31 | As at 2020-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||||||||||
| Net sales | — | — | — | — | — | — | — | — | — | — | 
                                                8,197,895,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,379,637,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,504,583,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,695,604,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,162,294,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,081,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,937,653,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,844,439,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                8,676,177,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,757,775,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | — | — | — | — | — | — | 
                                                93,305,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                115,392,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                84,115,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                99,808,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                367,770,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                368,731,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                124,549,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                172,947,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                192,654,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                274,733,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | — | — | — | — | — | — | — | 
                                                210,205,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,293,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                59,702,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                71,088,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                122,629,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | — | — | — | — | — | — | — | 
                                                558,262,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                28,958,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                165,754,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                253,624,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                8,806,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                8,238,304,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,171,441,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,900,147,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,722,616,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                7,748,025,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,066,794,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,631,172,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                7,063,157,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,419,677,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                6,995,658,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                12,577,525,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,461,367,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                9,795,597,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,640,313,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                11,756,424,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,102,830,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,735,139,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                10,129,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,405,724,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                10,012,436,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                4,506.66
                                                
                                             | 
                                                3,999.58
                                                
                                             | — | 
                                                3,847.95
                                                
                                             | 
                                                4,219.90
                                                
                                             | — | — | — | 
                                                4,231.61
                                                
                                             | 
                                                3,940.51
                                                
                                             | 
                                                4,172.42
                                                
                                             | — | — | 
                                                3,937.83
                                                
                                             | — | 
                                                4,061.67
                                                
                                             | — | 
                                                3,900.16
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | — | — | — | — | — | — | 
                                                77.49
                                                
                                             | 
                                                117.23
                                                
                                             | — | — | 
                                                -72.42
                                                
                                             | — | — | 
                                                -1.28
                                                
                                             | 
                                                44.23
                                                
                                             | 
                                                33.29
                                                
                                             | — | — | — | 
                                                35.63
                                                
                                             | 
                                                39.63
                                                
                                             | — | 
                                                48.76
                                                
                                             | — | 
                                                68.36
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | — | — | — | — | — | — |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — |  | — |  | — | 
| Equity-to-asset ratio | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                0.642
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.686
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.704
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.650
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.646
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.699
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.638
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.697
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.639
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.699
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | — | — | — | — | — | — | 
                                                0.020
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.027
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                -0.019
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.000
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.011
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.008
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.009
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.010
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.012
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.017
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | — | — | — | — | — | — | 
                                                16.0
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                38.9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                34.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                31.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                24.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                17.6
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | — | — | — | — | — | — | — | 
                                                659,910,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                50,565,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                201,402,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                412,349,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -56,953,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | — | — | — | — | — | — | — | 
                                                12,693,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -115,140,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -20,626,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -163,675,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -75,937,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | — | — | — | — | — | — | — | 
                                                -61,171,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -157,724,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -206,819,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                136,319,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -76,651,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                1,869,640,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,254,229,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                1,468,602,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,484,080,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                1,100,636,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Number of employees | 
                                                71
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                46
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                40
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                141
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                91
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                70
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                36
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                74
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                387
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                212
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                216
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                426
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                406
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                213
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                422
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                221
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                418
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                224
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                9
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                52
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                16
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                19
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                51
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                50
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                62
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                55
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                15
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |