Key Financial Data Of Reporting Company
| Concept | As at 2025-03-31 | 2024-04-01 to 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 | — | 
                                                262,732,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                248,681,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                186,930,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                197,431,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                179,619,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                185,961,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                161,126,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                162,929,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                156,194,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                157,712,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | 
                                                23,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                23,272,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,515,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                11,918,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,423,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                9,288,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,216,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,095,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                9,146,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                9,262,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | — | — | 
                                                17,508,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                8,799,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                6,775,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                5,863,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                6,242,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
| Share capital | — | — | 
                                                4,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                4,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                4,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                4,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                4,479,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | — | — | 
                                                45,963,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | 
                                                45,963,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                22,981,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | — | — | 
                                                22,981,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | — | 
                                                22,981,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | 
                                                109,206,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                101,727,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                93,987,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                88,795,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                80,689,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                82,424,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                77,242,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                75,779,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                74,837,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                73,178,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                215,309,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                195,721,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                160,553,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                151,193,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                144,312,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                148,544,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                139,099,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                136,750,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                132,210,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                129,750,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | 
                                                2,495.45
                                                
                                             | — | 
                                                2,372.02
                                                
                                             | — | — | — | 
                                                2,187.86
                                                
                                             | 
                                                2,072.12
                                                
                                             | — | 
                                                1,884.41
                                                
                                             | 
                                                1,920.67
                                                
                                             | — | — | — | 
                                                1,801.56
                                                
                                             | 
                                                1,771.12
                                                
                                             | 
                                                1,745.92
                                                
                                             | — | — | 
                                                1,711.91
                                                
                                             | 
| Dividend paid per share | — | — | — | 
                                                163.00
                                                
                                             | 
                                                103.00
                                                
                                             | — | — | — | 
                                                100.00
                                                
                                             | — | — | — | 
                                                90.00
                                                
                                             | — | — | — | — | 
                                                90.00
                                                
                                             | — | — | 
| Interim dividend paid per share | — | — | — | 
                                                52.00
                                                
                                             | 
                                                55.00
                                                
                                             | — | — | — | 
                                                45.00
                                                
                                             | — | — | — | 
                                                45.00
                                                
                                             | — | — | — | — | 
                                                45.00
                                                
                                             | — | — | 
| Basic earnings (loss) per share | — | 
                                                406.82
                                                
                                             | — | 
                                                408.34
                                                
                                             | 
                                                205.38
                                                
                                             | 
                                                212.10
                                                
                                             | — | — | 
                                                158.26
                                                
                                             | — | — | 
                                                154.78
                                                
                                             | 
                                                137.08
                                                
                                             | 
                                                135.08
                                                
                                             | — | — | — | 
                                                144.22
                                                
                                             | 
                                                145.98
                                                
                                             | — | 
| Diluted earnings per share | — |  | — |  |  |  | — | — |  | — | — |  |  |  | — | — | — |  |  | — | 
| Equity-to-asset ratio | 
                                                0.497
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.520
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.584
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.587
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.559
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.554
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.564
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.564
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | 
                                                0.174
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.184
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.104
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.087
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.083
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.079
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.076
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.089
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.089
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | 
                                                9.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                9.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                12.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                11.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7.5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                7.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.7
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                7.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                10.3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                10.1
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | — | — | 
                                                0.399
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.368
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.316
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                0.328
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                0.312
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
| Net cash provided by (used in) operating activities | — | 
                                                12,402,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                596,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                15,941,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -11,718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                14,241,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -832,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -603,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -4,729,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -873,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -718,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                16,044,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                -2,829,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                -2,218,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -3,214,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | 
                                                -3,487,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                50,552,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | — | — | 
                                                22,665,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                25,348,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
                                                16,037,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                31,747,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | — | 
| Number of employees | 
                                                2,445
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                2,070
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                2,221
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,007
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1,958
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                2,143
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                2,055
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,906
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                1,981
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1,867
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | — | — | 
                                                2.814
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.863
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.912
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                0.784
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.051
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | — | — | 
                                                1.896
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | 
                                                1.840
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.257
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | — | — | 
                                                1.181
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | — | 
                                                1.250
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |