China’s strong gun controls mean that fatal shootings are rare, and many citizens support the laws to keep it that way. But there has been a growing debate over the legal definition of a firearm. Experts say that China’s regulations — which ban buying, selling or owning weapons above a very low threshold of force — are vague and hard for laypeople, even judges, to understand. The result, critics say, is that unsuspecting buyers of compressed-air and spring-powered toys are turned into criminals.China’s gun control law of 1996 states that to be legally classified as a gun, a weapon has to be capable of killing someone or knocking them unconscious. But in 2010, the Chinese Ministry of Public Security imposed far stricter rules that in effect defined man …