Everybody knows about the Flying Tigers, the American air fighters group in China in WWII. Aside from the movies and all the narrative stuff, that was about a group of American personnel that acted in China, fighting side by side with Chinese against the forces of the Japanese Empire. They learned a lot from the experience made in Spain, where they fought against Italian and German pilots in the civil war that precedeed WWII.
But the Chinese were actively looking for warplanes in the ’30s, knowing for sure that war against Japan will come. So they looked for any option available, including purchasing Italian warplanes. So there was a time when the Kingdom of Italy supplied with machines and personnel and only the political decision to favor the Japanese side. In my country, referring to that years, there was somewhat a technological clash between those who favored a more traditional kind of airplane, biplanes, and those who were looking forward to the monoplane models inspired by American manifacturers.