Key Financial Data Of Group
| Concept | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | As at 2025-03-31 | 2024-04-01 to 2025-03-31 | As at 2025-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of group | ||||||||||||||||||||||||||||||
| Business results of group | ||||||||||||||||||||||||||||||
| Net sales | — | — | — | — | 
                                                154,920,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                5,819,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,627,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                138,253,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,178,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                127,822,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                4,256,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                120,644,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,456,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                112,618,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | — | — | — | 
                                                10,318,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                3,082,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,905,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,460,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                2,733,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,102,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,901,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,426,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                7,513,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) attributable to owners of parent | — | — | — | — | 
                                                6,657,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                12,253,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,923,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,646,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,015,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Comprehensive income | — | — | — | — | 
                                                6,677,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                13,380,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                5,808,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,369,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,873,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets | — | — | — | 
                                                65,395,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                26,333,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                61,007,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                24,462,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                22,470,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                48,375,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                43,673,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,083,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                39,706,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                21,302,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | — | 
                                                205,371,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                133,627,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                202,606,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                130,440,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                112,575,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                171,888,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                168,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                114,302,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                161,948,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                113,786,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | — | 
                                                2,746.37
                                                
                                             | — | — | — | — | 
                                                1,112.42
                                                
                                             | — | — | — | — | — | — | — | 
                                                2,510.23
                                                
                                             | 
                                                1,013.41
                                                
                                             | — | 
                                                932.65
                                                
                                             | 
                                                2,009.64
                                                
                                             | — | — | — | 
                                                1,819.55
                                                
                                             | 
                                                876.26
                                                
                                             | 
                                                1,631.59
                                                
                                             | — | — | 
                                                874.14
                                                
                                             | 
| Basic earnings (loss) per share | — | — | — | — | 
                                                280.28
                                                
                                             | — | — | — | — | — | — | — | 
                                                181.77
                                                
                                             | — | 
                                                114.62
                                                
                                             | 
                                                509.46
                                                
                                             | — | — | 
                                                107.67
                                                
                                             | — | — | 
                                                246.63
                                                
                                             | 
                                                63.81
                                                
                                             | 
                                                234.36
                                                
                                             | — | — | — | 
                                                79.17
                                                
                                             | 
                                                124.11
                                                
                                             | — | 
| Diluted earnings per share | — | — | — | — | 
                                                278.83
                                                
                                             | — | — | — | — | — | — | — | 
                                                180.83
                                                
                                             | — | 
                                                114.19
                                                
                                             | 
                                                507.56
                                                
                                             | — | — | 
                                                107.47
                                                
                                             | — | — | 
                                                246.18
                                                
                                             | 
                                                63.55
                                                
                                             | 
                                                233.40
                                                
                                             | — | — | — | 
                                                78.95
                                                
                                             | 
                                                123.76
                                                
                                             | — | 
| Equity-to-asset ratio | — | — | — | 
                                                0.315
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.196
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                0.298
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.187
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.199
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.281
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.259
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.245
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.187
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | — | 
                                                0.1065
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                0.1707
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.1178
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.2254
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.1191
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.1289
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0728
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.1357
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.0937
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.0788
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | — | 
                                                5.97
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                9.20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                15.32
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3.45
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                11.75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                5.13
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20.44
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                5.56
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                17.04
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.87
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | — | — | — | 
                                                4,018,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                5,266,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2,716,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                5,093,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                3,161,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | — | 
                                                -2,067,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                -16,541,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,860,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -4,671,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -3,078,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | — | 
                                                -1,329,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | 
                                                9,636,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -1,778,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -1,543,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                9,746,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | — | 
                                                9,162,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | — | — | — | — | — | 
                                                8,374,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                10,890,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                11,984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                249
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,878
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,067
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                537
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                29
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                100
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                356
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                89
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                435
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                272
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                2,031
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                81
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,454
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,451
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                71
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,349
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                66
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                167
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                178
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                20
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                83
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                47
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                166
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                112
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                132
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |