Sengoku period

The Sengoku Period (戦国時代 Sengoku jidai) or "warring-states" period, is a period of long civil war in the History of Japan that spans from the middle 15th to the early 17th centuries. It started in the late Muromachi period in 1467 with the Onin War (Onin no Ran 1467-1478), lasting through the entire Azuchi-Momoyama period, until final peace and order was achieved in 1615 of the Edo period.

Starting with and continuing after the Onin War, the central ruling authority of the Ashikaga or Muromachi Shogunate in the capital of Kyoto was ruined, leading to a complete breakdown in social order and civil war throughout Japan. Outside of the capital, the provincial daimyo and magistrates that relied on the shogunate for their own authority and power, found themselves isolated and vulnerable to not only external, but internal forces as well.

Gekokujō

Many of the provincial daimyō, such as the Shimazu, Takeda Shingen, and Yoshimoto Imagawa, having ruled their lands under the authority of not only the Ashikaga shogunate, but also under the preceding Kamakura shogunate, established their own independent domains. However, many others, like the Hosokawa, Shiba, and Toki found their lands taken over by their own subjects and retainers, like the Oda, late Hojo, and Saito Dosan, who had seized the opportunity to establish their own name and become new Sengoku daimyō in their own right. Also, peasants throughout Japan united with religious leaders and monks of the Buddhist True Pure Land sect to form Ikko-ikki to rebel against and resist the rule of the daimyō. In some cases they succeeded in forming their own independent domains, of which the most famous ikko ikki in Kaga province lasted independently for almost 100 years.

This phenomenon of social upheaval where the retainers and subjects came to reject traditions and values of the prior establishment and forcefully overthrow their leaders to establish their own independence became known as Gekokujō (下克上). Literally, gekokujō means the bottom overcomes/conquers the top.

Sengoku does not mean "warring states" but means "the age of the country at war"

Sengoku period in modern culture

• The game mod Sengoku is a FPS with feudal Japan theme and samurai for Battlefield 1942.
• The game Shogun: Total War is a real time strategy game set in Japan during Sengoku jidai.
• The anime and manga series InuYasha is set in the Sengoku period.
• The Soul Calibur series of video games are set in the period of transition between the Sengoku and Edo periods.
• The Samurai Warriors video game series by Koei takes place in this era.