Don't listen to Kaiser, China is interesting, but Japan is at least as interesting

To answer your question:
All medieval Japanese periods saw great masterminds of politics and warfare. Here's a list of the major periods:
Kamakura period: (1185-1333) Kamakura shogunate; transition into feudal era; rise of the warrior (samurai) class; two mongol invasions which were repelled mostly by tsunamis (kamikaze, the divine wind)
Muromachi period: (1336-1573) Ashikage shogunate; coalition of regional warlords; trade with Ming dynasty China
Sengoku period: (1467-1573) Civil wars; arrival of Portugese traders and other Europeans; introduction of firearms
Azuchi-Momoyama period: (1569-1603) Daimyo Oda Nobunaga almost unites Japan; finally united under Toyotomi Hideyoshi; invasion of Korea; two unsuccessful campaigns to conquer Ming China; return in 1598
Edo period: (1603–1868): Tokugawa Ieyasu seizes power and establishes the Tokugawa shogunate; central federation governement; administrated by over 200 daimyo; regulation of economy, religion and taxation; judiciary system; mostly peaceful era; complete seclusion from the outside world(Sakoku) until US intervention 1853
1868: Empire of Japan founded