The Satomi Sea Forces (6)

      In 1574, Yanada Harusuke (1524-1594), a standard-bearer of anti-Hojo forces, surrendered Sekiyado Castle, which Hojo Ujiyasu (1515-1571) had valued, “To occupy the castle is as valuable as to win one province.”  The castle was at the junction of 2 major river systems in the Kanto Plain, Tone-Watarase river system and Kinu river system, and was an important point of the water transportation in the region at that time.

     After the conquest, the Hojo Clan started its full-scale invasion of Boso Peninsula.  The Izu Sea Forces of the clan defeated the Satomi Sea Forces, and the Hojo Clan gained the naval superiority in Edo Bay.  In 1577, the Satomi Clan had to accept a peace treaty, and substantially retreated from Kazusa Province.