Key Financial Data Of Reporting Company
| Concept | As at 2024-06-30 | 2023-07-01 to 2024-06-30 | As at 2023-06-30 | 2022-07-01 to 2023-06-30 | 2021-07-01 to 2022-06-30 | As at 2022-06-30 | 2020-07-01 to 2021-06-30 | As at 2021-06-30 | As at 2020-06-30 | 2019-07-01 to 2020-06-30 | 
|---|---|---|---|---|---|---|---|---|---|---|
| Key financial data of reporting company | ||||||||||
| Business results of reporting company | ||||||||||
| Net sales | — | 
                                                1,652,097,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,353,869,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                910,399,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                706,857,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                692,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Ordinary profit (loss) | — | 
                                                344,020,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                204,135,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                67,651,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -198,538,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -626,939,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Profit (loss) | — | 
                                                403,751,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                228,532,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                91,967,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -210,748,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                -676,867,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Equity in earnings (losses) of affiliates if equity method is applied | — | 
                                                4,003,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,234,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                10,307,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                7,716,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Share capital | 
                                                52,103,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                100,000,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total number of issued shares | 
                                                4,720,947
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                3,636,000
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | — | 
                                                1,062
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
                                                1,062
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | 
                                                1,062
                                                
                                                    
                                                        xbrli:shares
                                                    
                                                
                                             | — | 
| Net assets | 
                                                3,638,348,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,166,377,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                937,844,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                845,877,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,056,715,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Total assets | 
                                                4,101,519,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,576,114,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                1,302,936,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                1,198,917,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                1,326,192,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Net assets per share | 
                                                770.37
                                                
                                             | — | 
                                                320.34
                                                
                                             | — | — | 
                                                -149.46
                                                
                                             | — | 
                                                -178.32
                                                
                                             | 
                                                -112.18
                                                
                                             | — | 
| Dividend paid per share | — |  | — |  |  | — |  | — | — |  | 
| Interim dividend paid per share | — |  | — |  |  | — |  | — | — |  | 
| Basic earnings (loss) per share | — | 
                                                86.70
                                                
                                             | — | 
                                                62.85
                                                
                                             | 
                                                25.29
                                                
                                             | — | 
                                                -57.96
                                                
                                             | — | — | 
                                                -192.86
                                                
                                             | 
| Diluted earnings per share | — | 
                                                77.26
                                                
                                             | — |  |  | — |  | — | — |  | 
| Equity-to-asset ratio | 
                                                0.887
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.739
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                0.719
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.704
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.796
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Rate of return on equity | — | 
                                                0.168
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                0.218
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                0.103
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Price-earnings ratio | — | 
                                                28.8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Payout ratio | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
| Net cash provided by (used in) operating activities | — | 
                                                285,510,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                150,321,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -55,735,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -179,471,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) investing activities | — | 
                                                -37,048,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -36,874,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -103,371,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -8,360,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Net cash provided by (used in) financing activities | — | 
                                                1,980,215,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                -60,100,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                -5,400,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                75,895,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
| Cash and cash equivalents | 
                                                2,900,488,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                671,809,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | — | 
                                                618,463,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
                                                782,969,000
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        JPY
                                                    
                                                
                                             | — | 
| Number of employees | 
                                                97
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                85
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                70
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                69
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                73
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Average number of temporary employees | 
                                                8
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                10
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Total shareholder return | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
| Total return on share price index | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | 
                                                
                                                
                                                    
                                                        xbrli:pure
                                                    
                                                
                                             | — |