The period in Japan
's history from the establishment of the Kamakura shogunate after the Genpei war
and the end of the Heian era
in 1192 untill its fall in 1333. It was the beginning of the era of shoguns, the feudal
period ruled by military
warrior (bushi) class.
After the house or Taira (also called the Heike) was destroyed, Minamoto Yoritomo, the leader of the house of Genji, requested (well, threatened) the emperor for the sovereignty to rule Japan. The emperor conferred on him the title and post of Seii-tai-shogun. This was an emergency post with the power to command the whole military armies for the purpose of "conquering barbarians". The post was nominally one that was held under the pleasure of the emperor. But in fact, a shogun could deploy armies without emperor's permission, so he was the strongest single person in Japan.
He established his own military government at the city of Kamakura , independent from the emperor and its bureaucracy in Kyoto, and named it Bakufu (literally "tent govenment"). After that, Japan was to be ruled by a series of the military governments of shogunates for 700 years.
Minamoto-no-Yoritomo died shortly after he founded the Kamakura shogunate, and his successors died soon, too. The house Genji perished when the third shogun Minamoto-no-Sanetomo was assassinated in 1219.
The emperor Gotoba in Kyoto thought this was an opportunity to destroy the shogunate and take back sovereignty under his own hand. He raised an army in 1221. In this crisis, Hojo Masako, the widow of Yoritomo and the mother of Sanetomo, called the bushi throughout the country as the regent of shogun. Most bushi chose to follow Masako. The shogunate army led by Hojo Yasutoki marched to Kyoto and defeated the imperial army. After this, the imperial house was entirely under control of the Kamakura shogunate.
Following the attempted Mongol invasions in 1281 there was discontent among the warriors who had fought bravely but had not been rewarded (the shogunate was bankrupt).
The emperor Godaigo seized this opportunity. He gathered together the disastified bushi, including Ashikaga Takauji, Nitta Yoshisada, and Kusunoki Masashige, to raise an army against the Hojo Regency. The army defeated the Hojo, and in 1333 the emperor declared the Shogunate abolished.
However, the emperor rewarded the nobility first, who had not actually fought in the front lines of the battles. So the warrior class became discontented again. Finally Ashikaga Takauji rebelled against the dynasty. He drove the emperor Godaigo away from Kyoto, and put forward a new emperor to appoint himself the new shogun in 1336. This was the establishment of the Muromachi or Ashikaga era.
The emperor Godaigo escaped south to Mount Yoshino, and declared himself the only legitimate emperor. Of course, Ashikaga Takauji supported the new emperor in Kyoto. There were thus now two dynasties. This period is called Nanbokucho, the "Northern and Southern dynasties." This schism lasted until 1392.
You can go back to the Heian period or forward to the Muromachi period.