The Sengoku period (戦国時代 Sengoku jidai?, lit. Age of Civil War; c. 1467 – c. 1603) is a period in Japanese history marked by social upheaval, political intrigue and near-constant military conflict. Japanese historians named it after the otherwise unrelated Warring States period in China. It came to an end when all political power was unified under the Tokugawa shogunate.
During this period, although the Emperor of Japan was officially the ruler of his nation and every lord swore loyalty to him, he was largely a marginalised, ceremonial, and religious figure who delegated power to the Shogun, a noble who was roughly equivalent to a Generalissimo. In the years preceding this era the Shogunate gradually lost influence and control over the daimyōs (local lords). Although the Ashikaga shogunate had retained the structure of the Kamakura shogunate and instituted a warrior government based on the same social economic rights and obligations established by the Hōjō with the Jōei Code in 1232, it failed to win the loyalty of many daimyōs, especially those whose domains were far from the capital, Heian-kyō. Many of these Lords began to fight uncontrollably with each other for control over land and influence over the shogunate. As trade with China grew, the economy developed, and the use of money became widespread as markets and commercial cities appeared. This, combined with developments in agriculture and small-scale trading, led to the desire for greater local autonomy throughout all levels of the social hierarchy. As early as the beginning of the 15th century, the suffering caused by earthquakes and famines often served to trigger armed uprisings by farmers weary of debt and taxes.