A stone wall of Koriyama Castle in Yamatokoriyama, Nara Prefecture, that was built in the 16th century, will be open to the public on Nov. 14 and 15, offering a rare glimpse of the inner structure of a castle wall, according to city officials.

The castle was run by Toyotomi Hidenaga (1540-1591), the younger brother of warlord Toyotomi Hideyoshi.

The 9-meter-high wall is believed to have been the foundation for the castle's donjon, or fortified central tower, which is no longer standing.

The wall was built through the piling up of stones, with the largest of these weighing about 2.8 tons, according to the officials. The wall is currently being dismantled, partly for repair work.

Details about the main tower were unknown until last year, when 23 cornerstones were discovered through excavation, indicating the building must have been more than 15 meters high.