In late 1945 after the war ended, US scientists and military officials found and tested out a prototype of J7W, they were so impressed that in early 1946 they gathered the Watanabe engineers and gave them a very secret task to build a similar plane, but for use in navy. Because the Cold War started some US military leaders were thinking about giving Japan some of their carriers in case of emergency and these carriers we planned to be equipped with new Watanabe planes. In 1947 the first prototype was built. It was equipped with an American engine and armed with a few 13.2mm Japanese Type 3 machine guns left in the storage. But though the plane genuinely impressed the military, the government's policy changed and it was decided that it was too risky to give Japan a brand-new fleet. So the project was stopped. There are some rumors that Watanabe secretly built a half-dozen of these planes by the time of 1950. A small squad of them piloted by some Japanese veteran pilots not willing to surrender operated in the Korean war, fighting against China, but due to lack of spare parts one by one all these planes were shot down or scrapped, while all documentation on this plane was destroyed in a fire