 Both the Toyotomi and Tokugawa governments encouraged the Nanbu to build a strong fortification, partly as a counter to the strength of the Date clan to the south.The Inner bailey is a square area approximately 60 meters on a side, with a large gate on its eastern end.In the southern corner was a three-story "yagura", which served as the "tenshu" after the main tower was lost in a fire in 1634.