Igashi no Hen (Incident of the Iga clan) (伊賀氏の変)
Igashi no Hen is a political turmoil that happened in the Kamakura bakufu (Japanese feudal government headed by a shogun), which lasted about a month from June 1224 in the early Kamakura period. Due to the death of Yoshitoki HOJO, Mistumune IGA and Iga no kata, his younger sister and the second wife of Yoshitoki, schemed to have Masamura HOJO, her biological son, to assume the position of shikken, regent to the shogunate, and to have Sanemasa ICHIJO, her son-in-law, to assume the Shogunship.
Mitsumune IGA approached Yoshimura MIURA, a powerful Gokenin, the shogunal retainer of the Kamakura bakufu. The Ama Shogun (the nun-shogun) Masako HOJO, sensing the threatening move of the Iga clan, had Yasutoki HOJO, the oldest son of Yoshitoki HOJO, assume the position of Shikken. She succeeded in preventing the political change the Iga clan plotted by ensuring Yoshimura MIURA's commitment to support Yasutoki HOJO.
Although Iga no kata, Mitsumune IGA, and Sanemasa ICHIJO were exiled for the plot, Masamura HOJO, whom they tried to make the regent, escaped severe punishment and assumed the seventh Shikken position later.
The common belief stated above is a theory which identified the "rumor" of the Iga clan's rebellion described in the article of June 28th of Joo era in "Azuma Kagami" (a chronicle of the early history of the Kamakura bakufu) as a fact. In "Azuma Kagami," it is stated that Yasutoki HOJO had investigated on the matter before entering the capital of Kamakura, and denied the rebellion of the Iga clan as "an untrue rumor which should not be made a fuss about."
Some say Masako HOJO, in fear of decline of her own influence in the Kamakura bakufu due to having no blood relationship with the Shogun family and the weak connection with the head family of HOJO, designed this incident, which has the same content with the Incident of Maki clan, in order to forcibly ruin the Iga clan, who were to hold strong power as Yoshitoki's widow. Yasutoki HOJO, not taken in by Masako's plot, calmed the state of affairs, and had Mitsumune IGA and others who were punished by Masako reinstated to the Kamakura bakufu.