The Chinese Air Force has established a training unit to accurately (as possible) portray enemy (especially American and Indian) aircraft and combat tactics. Thus there are three Blue-Army Aggressor Squadrons (Blue is the bad guys in Chinese training, Red is the good guys) for this. One is equipped with Su-30s, to represent American F-15s or Indian Su-30s. Another has the J-10A, which is similar to the F-16. The third squadron has J-7s (Chinese copies of the MiG-21), which represent low end threats, like the many MiG-21s India still uses.
Using your own aircraft for “aggressor (or dissimilar) training” began in the 1969, when the U.S. Navy established the original “Top Gun” fighter pilot school. This was done in response to the poor performance of its pilots against North Vietnamese pilots flying Russian fighters. What made the Top Gun operation different was that the training emphasized how the enemy aircraft and pilots operated. This was called “dissimilar training”. In the past, American pilots practiced against American pilots, with everyone flying American aircraft and using American tactics. It worked in World War II, because the enemy pilots were not getting a lot of practice and were using similar aircraft and tactics anyway. Most importantly, there was a lot of aerial combat going on, providing ample opportunity for on- the- job training. Not so in Vietnam, where the quite different Russian trained North Vietnamese were giving U.S. aviators an awful time. The four week Top Gun program solved the problem. The air force followed shortly with its Red Flag school. In the early 1980s, the Russians established a dissimilar air combat school, and the Chinese followed in 1987.