Aotsuka Kofun

The is a Kofun period burial mound, located in the Aotsuka neighborhood of the city of Inuyama, Aichi in the Tōkai region of Japan. It was designated a National Historic Site of Japan in 1983. It is the second largest "kofun" found in Aichi Prefecture after the Danpusan Kofun in Nagoya.
Overview.
The Aotsuka Kofun is located in the southern part of Inuyama, in western Aichi Prefecture. It is one of tumuli which once formed a "kofun" cluster in the surrounding area (most of which have now been destroyed). Archaeological excavations have been conducted several times since 1979. 
The tumulus is a , which is shaped like a keyhole, having one square end and one circular end, when viewed from above. It has a total length of 123 meters and is orientated to face southwest. It consists of a three-tiered posterior circular portion with a diameter of 78 meters and height of 12 meters, and a two-tier trapezoidal anterior portion, with a width of 62 meters, length of 45 meters and height of seven meters. The tumulus was formerly covered in "fukiishi" across its entire surface, and had rows of cylindrical and drum-shaped "haniwa". It is believed to have been built in the middle of the 4th century in the early Kofun period. 
The "kofun" is associated with the "Ni-no-miya" of Owari Province, Oagata Jinja, which is located 3.5 kilometers to the east. The shrine claims that the "kofun" is the grave of its "kami", . During the Sengoku period, the tumulus was fortified as a castle by the forces of Toyotomi Hideyoshi during the 1584 Battle of Komaki and Nagakute.
The site is now open to the public with the exterior of the tumulus restored to its the appearance at the time of construction as part of the Aozuka Kofun Historical Park , which also has an on-site museum. It is located about a 30-minute walk from Gakuden Station on the Meitetsu Komaki Line.