Key Financial Data Of Reporting Company
| Concept | As at 2025-02-28 | 2024-03-01 to 2025-02-28 | 2023-03-01 to 2024-02-29 | As at 2024-02-29 | 2022-03-01 to 2023-02-28 | As at 2023-02-28 | 2021-03-01 to 2022-02-28 | As at 2022-02-28 | 2020-03-01 to 2021-02-28 | As at 2021-02-28 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||
| Business results of reporting company | ||||||||||
| Net sales | — | 
                                                1,504,315,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,467,931,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,455,568,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,402,554,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,242,218,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Ordinary profit (loss) | — | 
                                                13,713,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                50,575,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                56,246,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                41,506,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -387,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Profit (loss) | — | 
                                                -16,676,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                52,589,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                44,333,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                33,881,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                2,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -11,831,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Share capital | 
                                                213,128,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                213,128,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                212,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                212,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                212,928,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total number of issued shares | 
                                                1,440,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                1,440,600
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                720,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                720,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                720,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
| Net assets | 
                                                361,967,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                378,643,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                326,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                281,819,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                247,583,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Total assets | 
                                                728,022,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                595,703,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                641,618,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                616,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                628,945,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net assets per share | 
                                                248.53
                                                
                                             | — | — | 
                                                260.11
                                                
                                             | — | 
                                                223.42
                                                
                                             | — | 
                                                192.63
                                                
                                             | — | 
                                                171.93
                                                
                                             | 
| Dividend paid per share | — |  |  | — |  | — |  | — |  | — | 
| Interim dividend paid per share | — |  |  | — |  | — |  | — |  | — | 
| Basic earnings (loss) per share | — | 
                                                -11.58
                                                
                                             | 
                                                36.51
                                                
                                             | — | 
                                                30.79
                                                
                                             | — | 
                                                23.53
                                                
                                             | — | 
                                                1.92
                                                
                                             | — | 
| Diluted earnings per share | — |  | 
                                                36.43
                                                
                                             | — | 
                                                30.69
                                                
                                             | — | 
                                                23.46
                                                
                                             | — | 
                                                1.91
                                                
                                             | — | 
| Equity-to-asset ratio | 
                                                0.492
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.629
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.501
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.450
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.387
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Rate of return on equity | — | 
                                                -0.046
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.151
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.148
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.130
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.011
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Price-earnings ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                14.79
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                19.62
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                28.03
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                251.98
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Payout ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) operating activities | — | 
                                                30,115,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                18,555,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                101,484,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                136,403,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -108,583,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) investing activities | — | 
                                                -28,556,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -18,687,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -49,007,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -20,358,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                27,098,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net cash provided by (used in) financing activities | — | 
                                                165,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -55,082,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -60,810,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -63,325,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                67,670,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Cash and cash equivalents | 
                                                368,045,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                200,548,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                255,763,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                264,096,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                211,376,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Number of employees | 
                                                75
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                67
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                71
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                65
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                63
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Average number of temporary employees | 
                                                3
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                4
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                5
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total shareholder return | 
                                                0.859
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.381
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.507
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.105
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Total return on share price index | 
                                                1.775
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                1.771
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.319
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.249
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                1.234
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             |