A retainer of Mogami Yoshiaki, Tan Yosozaemon was ordered in 1581 to build a castle at Kaneyama, at the foot of the Ariya Pass dividing Mogami district from Akita's Ogachi district, as part of Yoshiaki's campaign against Onodera Yoshimichi. He subsequently garrisoned the castle as the front line against the Onodera clan of Senboku, repeatedly leading sorties in the skirmishes that frequently broke out near the Ariya Pass. The street layout of present-day central Kaneyama town in Mogami district, Yamagata, is said to date from his time developing the castle town.

A hands-on castellan who not only built the castle but planned its town layout, repeatedly leading sorties himself on the frontier.

The street layout he established for the Kaneyama castle town remains the basis of the town's streets today, a lasting trace of his governance.