Timeline of Key Events in Shogun Japan (1185–1868) By Reiss Period: 1582 to 1590 Oda Nobunaga unifies much of Japan Powerful warlord who began Japan’s unification using advanced military tactics. 1603 Tokugawa Ieyasu becomes shogun (start of Edo period) Began the Tokugawa Shogunate, a time of peace, order, and isolation.