Donkatsu Gwangjang is a second-floor diner near Jongno 5-ga and Dongdaemun Market that serves donkatsu and udon. The gwangjang donkatsu comes as two pieces of thick meat in a crisp coating, and the shop also sells gukmul tteokbokki and twumba donkatsu. Orders are placed at a kiosk, food is brought out, and everything else is self-service. The basic donkatsu portion is large, so it is worth ordering less than you think you want.