sengoku jidai
A period of feudal Japan between around circa 1450 to 1600 in which the country was divided among various clans of warlords who fought for dominance over the others, following the decline of the Ashikaga Shogunate at the end of the Nanboku-chou Jidai.
The period reached its climax around 1540 when the "three great unifiers" of Japan emerged; Oda Nobunaga who managed to unify Japan by force before being forced to commit suicide after being betrayed by Akechi Mitsuhide, Toyotomi Hideyoshi, Nobunaga's retainer who revenged his master by killing Mitsuhide and unify Japan, before faced his downfall after a failed invasion of Korea in 1598, and Tokugawa Ieyasu, another of the Nobunaga's retainer who waited for an opportunity and seized all of remnants of Toyotomi and Oda clans and finally unified the country after the battle of Sekigahara.
The era ended with Japan being united under the leadership of the Tokugawa shogunate who closed the country and started the Edo period. Due to being one of the most prevalent era in Japanese history, several media franchises have emerged based on it. It also has influenced various media works in the country.