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 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…