National Treasures (国宝: kokuhō) are the most precious of Japan's Tangible Cultural Properties, as determined and designated by the Agency for Cultural Affairs (a subsidiary of the Ministry of Education, Culture, Sports, Science and Technology). A Tangible Cultural Property is considered to be of historic or artistic value, classified either as "buildings and structures", or as "fine arts and crafts". Each National Treasure must show outstanding workmanship, a high value for world cultural history, or exceptional value for scholarship.
Approximately 20% of the National Treasures are structures such as castles, Buddhist temples, Shinto shrines, or residences. The other 80% are paintings, scrolls, sutras, works of calligraphy, sculptures of wood, bronze, lacquer or stone, crafts such as pottery and lacquerware carvings, metalworks, swords and textiles, and archaeological and historical artifacts. The items span the period of ancient to early modern Japan before the Meiji period, including pieces of the world's oldest pottery from the Jōmon period, to 19th-century documents and writings. The designation of the Akasaka Palace in 2009 added a 20th-century National Treasure.
Matsumoto Castle (松本城, Matsumoto-jō?), also known as the "Crow Castle" (烏城, Karasu-jo?) because of its black exterior, is one of Japan's premier historic castles. It is located in the city of Matsumoto, in Nagano Prefecture and is within easy reach of Tokyo by road or rail.
Matsumoto Castle is a flatland castle (hirajiro) because it is not built on a hilltop or amid rivers, but on a plain. Its complete defences would have included an extensive system of inter-connecting walls, moats and gatehouses.