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 " daimyo " , such as Oda Nobunaga , Toyotomi Hideyoshi or Tokugawa Ieyasu , struggled to unify Japan . During the Sengoku period , because of constant warfare , a large number of fortifications and castles were built . Archetypal Japanese castle construction is a product of the Momoyama period and early Edo period . A new era of castle construction began when the daimyo Nobunaga built Azuchi Castle from 1576 to 1579 . Earlier fortifications of the Kamakura and Muromachi periods were crude large scale structures ; Azuchi , however , with rich ornamentation and a keep rising seven stories high , became the prototype for castle construction of the period . The style of Azuchi Castle marked a shift in the function of the castles from a place that was merely a fortress and military garrison to a political , cultural and economic center . The newer style castles functioned as home to the " daimyo " , his family , and his most loyal retainers . Because of the expense of building such a lavish structure , castles in the style of Azuchi , functioned also to highlight the power and prestige of the daimyo . These new castles were built of wood and plaster on a stone foundation . Generally the main keep or " tenshu " was positioned at the highest point , surrounded by a series of interlocking baileys with walls , small towers and pathways . Residential buildings were located in one of the outer circles . The " daimyo " conducted his business in the citadel . Almost 100 major castles were built between 1596 and 1615 . The peak of castle - building occurred during the years 1600 to 1615 : in 1600 Tokugawa Ieyasu defeated the Toyotomi clan in the Battle of Sekigahara ; and in 1615 the Toyotomi forces were finally destroyed in the Siege of Osaka . The Tokugawa shogunate then limited the number of castles to one per province ; and banned the building of new castles entirely in 1620 . By the time of the Meiji Restoration in the late 19th century , castles were in a state of disuse and neglect . Seen as symbolic of the ruling elite of previous eras , some castles were dismantled and sold as firewood . Others were destroyed by fire , earthquake or typhoon . Only twelve castles have a " donjon " that is considered " original " . The term " National Treasure " has been used in Japan to denote cultural properties since 1897 . The definition and the criteria have changed since the inception of the term . These castle structures adhere to the current definition , and were designated national treasures when the Law for the Protection of Cultural Properties was implemented on June 9 , 1951 . The items are selected by the Ministry of Education , Culture , Sports , Science and Technology based on their " especially high historical or artistic value " . This list presents eight entries of National Treasures from four castles built during the late Momoyama to early Edo period ; however , the number of structures is actually more because in some cases multiple structures have been combined to form a single entry . The structures listed include " donjon " , watch towers and connecting galleries . Statistics . The eight national treasures are distributed over four castles as follows : Himeji Castle has five national treasure structures ; Hikone Castle , Inuyama Castle and Matsumoto Castle each have one . Three main types of castles exist . Generally the types are characterised according to the topography of the castle ' s site and named accordingly : , which are castles built on hills in a plain such as Himeji Castle , Hikone Castle , and Inuyama Castle . The " donjon " can be constructed in two ways . In the older ( " irimoya " ) style roofs . Hikone Castle , Himeji Castle and Inuyama Castle are representative of this style . The Matsumoto Castle has a virtually square foundation . Each level is slightly smaller than the one below but maintains the same shape . Only in rare cases the " donjon " stands independent of other structures . Generally it is connected to smaller watch towers called " yagura " , either directly ( ) or via a in which case the style is called . Matsumoto Castle has both styles , " renketsushiki " in the northwest and " fukugōshiki " in the southeast . At Himeji Castle three watch towers , four connecting galleries and the main " donjon " enclose a small courtyard . A typical keep would have between three and seven stories discernible from the outside . Its inner structure including the number of floors could differ from the outward appearance . Castle towers at Himeji , Inuyama and Matsumoto Castle have one floor more than is visible from the outside . Usage . The table ' s columns ( except for " Images " ) are sortable pressing the arrows symbols . The following gives an overview of what is included in the table and how the sorting works .