Char siu (叉烧) is a Cantonese style roast pork that's sweet and savory and usually known for it's red color. Chāshū (チャーシュー), on the other hand, is a Japanese adaptation of Chinese char siu but prepared totally different. Chashu is made with a rolled up log of pork belly braised in a concoction of soy sauce, sake, and sugar. It's often served sliced, as a topping on ramen.