Most people visit Matsumoto to see its magnificent 16th century castle. Matsumoto Castle's five-tiered main keep is the oldest in Japan and is very well preserved as it was never used in battle. The castle is nicknamed Karuso-jo (Crow Castle) due to its shape, and others believe, its black wooden walls. Inside are actually 6 floors, and each displays defensive weapons such as armor, guns, swords, and archer niches. The Moon-viewing Turret is the most famous of this castle and was built in the 1630s for aesthetic purposes. Also on the grounds is the Japanese Folklore Museum, and Japan Ukiyo-e Museum, specializing in woodblock prints.