The Ikedaya incident (池田屋事件, Ikedaya jiken), also known as the Ikedaya affair or Ikedaya riot, was an armed encounter between the shishi which included masterless samurai (rōnin) formally employed by the Chōshū, Tosa and Higo domains (han), and the Shinsengumi, the Bakufu's special police force in Kyoto on July 8, 1864, at the Ikedaya Inn in Sanjō-Kawaramachi, Kyoto, Japan.
The Shinsengumi (新選組, "Newly Selected Corps") was a small secret police organization, an elite group of swordsmen organized by commoners and low-ranking samurai, commissioned by the bakufu (military government) during Japan's Bakumatsu period (late Tokugawa shogunate) in 1863. It was active until 1869. It was founded to protect shogunate representatives in Kyoto at a time when a controversial imperial edict to exclude foreign trade from Japan had been made and the Chōshū clan had been forced from the imperial court. They gained considerable fame from events such as the Ikedaya incident and the August 18 coup, among others. The members were drawn from the sword schools of Edo.