Playing is an important way for children to develop physical, mental, and social skills. But a good toy needs to be more than developmentally useful; it has to be fun. We sent Karis Duncan to the International Tokyo Toy Show to find out what kind of fun Japanese toy makers have in store for us, including an educational system using AR and motion capture, tasty-smelling silicone putty, miniaturized classic arcade games, toy guns with eco-friendly firepower, and much more.