He is said to have built Niju-bashi Bridge (stone bridge of the Main Gate) of the Imperial Palace as well; however, since the bridge is said to have been completed in 1887, it is not clear whether the bridge was actually a work by Kangoro.
皇居の二重橋（正門石橋）も架けたと言われるが、明治20年完成とされており勘五郎の作かは定かでない。