Key Financial Data Of Reporting Company
| Concept | 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 | 2024-04-01 to 2025-03-31 | 2023-04-01 to 2024-03-31 | 2023-04-01 to 2024-03-31 | As at 2024-03-31 | As at 2024-03-31 | 2022-04-01 to 2023-03-31 | As at 2023-03-31 | As at 2023-03-31 | 2022-04-01 to 2023-03-31 | 2021-04-01 to 2022-03-31 | 2021-04-01 to 2022-03-31 | As at 2022-03-31 | As at 2022-03-31 | As at 2021-03-31 | 2020-04-01 to 2021-03-31 | 2020-04-01 to 2021-03-31 | As at 2021-03-31 | 
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||||||||||||||||
| Business results of reporting company | ||||||||||||||||||||||||
| Net sales | — | — | — | 
                                                858,082,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                12,674,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                5,130,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                832,595,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                4,448,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                606,890,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                428,401,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                433,970,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Operating revenue | — | — | — | — | — | — | — | 
                                                19,501,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                21,121,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                17,881,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                23,699,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                20,728,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Ordinary profit (loss) | — | — | — | 
                                                11,320,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -4,683,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                6,126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                358,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                5,892,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                50,560,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,955,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                30,028,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,460,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                25,506,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | — | — | — | — | 
                                                -1,055,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                17,145,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                2,358,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -53,215,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -5,117,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | — | — | — | 
                                                23,885,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                23,798,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,733,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                23,672,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                23,611,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | — | — | — | 
                                                259,618,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                259,481,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                259,409,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                259,336,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                259,214,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | — | — | 
                                                392,260,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                238,209,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                387,885,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                249,398,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                240,043,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                397,981,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                387,662,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                261,539,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                417,616,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                316,984,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | — | — | 
                                                784,175,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                439,472,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                792,296,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                412,562,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                395,192,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                713,127,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                694,274,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                417,396,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                702,529,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                458,666,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | — | — | 
                                                1,616.43
                                                
                                             | — | — | 
                                                985.65
                                                
                                             | — | — | — | — | 
                                                1,598.71
                                                
                                             | 
                                                1,032.53
                                                
                                             | — | 
                                                997.73
                                                
                                             | 
                                                1,651.54
                                                
                                             | — | — | — | 
                                                1,532.72
                                                
                                             | 
                                                1,035.45
                                                
                                             | 
                                                1,652.19
                                                
                                             | — | — | 
                                                1,255.55
                                                
                                             | 
| Dividend paid per share | — | — | — | — | — | — | — | 
                                                40.00
                                                
                                             | 
                                                40.00
                                                
                                             | — | — | — | 
                                                38.00
                                                
                                             | — | — | — | 
                                                15.00
                                                
                                             | — | — | — | — | 
                                                12.00
                                                
                                             | — | — | 
| Interim dividend paid per share | — | — | — | — | — | — | — |  |  | — | — | — |  | — | — | — |  | — | — | — | — |  | — | — | 
| Basic earnings (loss) per share | — | — | — | 
                                                -1.65
                                                
                                             | — | — | — | 
                                                -4.37
                                                
                                             | 
                                                71.11
                                                
                                             | 
                                                -32.48
                                                
                                             | — | — | 
                                                9.41
                                                
                                             | — | — | 
                                                122.28
                                                
                                             | 
                                                -210.72
                                                
                                             | 
                                                -140.77
                                                
                                             | — | — | — | 
                                                -20.27
                                                
                                             | 
                                                20.37
                                                
                                             | — | 
| Diluted earnings per share | — | — | — |  | — | — | — |  | 
                                                71.10
                                                
                                             |  | — | — | 
                                                9.41
                                                
                                             | — | — | 
                                                122.27
                                                
                                             |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | — | — | 
                                                0.498
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.542
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.487
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.605
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.607
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.557
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.558
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.627
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.594
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.691
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | — | — | 
                                                -0.001
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                -0.004
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.070
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                -0.020
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.009
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.078
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                -0.184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                -0.088
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                -0.016
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.013
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                20.95
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                174.39
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                13.42
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                66.57
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.563
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                4.040
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | — | — | 
                                                46,761,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                11,090,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                110,769,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                19,311,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                12,467,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | — | — | 
                                                -21,172,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -20,201,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -11,471,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -7,695,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -13,520,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | — | — | 
                                                -15,049,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -8,894,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -61,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -148,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                196,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | — | — | 
                                                332,761,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | — | — | 
                                                324,507,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                332,755,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                288,009,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                268,281,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                1,128
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                6,332
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                8,365
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                469
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                248
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                436
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                8,865
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                249
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                313
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,876
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                7,275
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                283
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7,371
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                278
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                308
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,870
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,356
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                65
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                60
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                113
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                2,720
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                46
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                67
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,516
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1,794
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                53
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,863
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                48
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | — | — | — | 
                                                1.522
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.838
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.965
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.718
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.576
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | — | — | — | 
                                                2.134
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                2.168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.534
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.450
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.421
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |