List of National Treasures of Japan (castles)
The Japanese Sengoku period from the mid-15th to early 17th century was a time of nearly continual military conflict. Powerful military lords known as daimyōs, such as Oda Nobunaga, Toyotomi Hideyoshi, and Tokugawa Ieyasu, struggled to unify Japan.
Source: Wikipedia — List of National Treasures of Japan (castles) (CC BY-SA 4.0)