Because Hikone-jo Castle was too large for a daimyo with 35, 000 koku, the Bakufu ordered other daimyos for tetsudai bushin (a large-scale engineering work by federal lords under shogun's order) to build the castle.
彦根城は35万石の大名としては、城郭が大きすぎ、築城にあたっては幕府が諸大名に手伝普請をさせた。