Japan has grounded all of its F-15J fighters until it can figure out what exactly caused one of its F-15s to shed several parts during a recent air show. Seven pieces fell off the aircraft as it made a sharp turn..
This sort of thing makes Japan even more eager to find a modern fighter to replace its 118 F-4 and 202 F-15 aircraft. With China and Russia putting more new fighters into service, Japan sees a threat. Japan has made several efforts to buy the U.S. F-22, without success. The United States does not want to export its premier air superiority fighter. Japan believed the U.S. F-35 was not the solution to its needs, and the Eurofighter and Rafle have not made the cut either. But now it's been decided to buy some F-35s, just to stay ahead of Russia and China. But there remains the possibility of designing and building their own advanced fighter.
Japan has built its own fighters recently. In the 1990s, it designed and built a modified version of the U.S. F-16. That proved to be a financial disaster, with each of the 22 ton F-2s cost $120 million. While a bit larger, and somewhat more capable, than contemporary F-16s, the cost was about four times as much. Only 98 were built, rather than the 141 originally planned. The aircraft entered service seven years ago.
It's been suggested that Japan try to design and built a stealthy "F-3". In addition to being very expensive, this would still require a lot of American technology. Japan builds fighter jet engines under license, and could probably get licenses to enough of that technology so that it could design an engine for its new fighter. Japan is already a leader in developing and manufacturing aircraft electronics. But a major problem remains the high costs of developing and building weapons inside Japan (where wage and benefits costs are quite high). However, Japanese voters and politicians are increasingly inclined to change post World War II laws that prohibit Japan from exporting weapons. That could make the "F-3" feasible.