In 1601, Honda Tadakatsu, one of the Four Guardian Kings of the Tokugawa, entered Kuwana as its first domain lord with a stipend of 100,000 koku and took control of the castle. He expanded the fortifications by enclosing the main, second, and third baileys with moats and reoriented the castle to open toward the sea, while also carrying out the large-scale "Keicho town planning" project that developed Kuwana into a castle town, post station, and port.