Kansei Igaku no Kin (the Kansei Prohibition of Heterodox Studies) (寛政異学の禁)
Kansei Igaku no Kin was an academic control performed during the Kansei Reforms in 1790, by a roju (senior councilor) of the Edo Shogunate, Sadanobu MATSUDAIRA.
In order to regain leadership after going through the Tenmei Famine in times of Okitsugu TANUMA, the shogunate chose Neo-Confucianism out of Confucianism for the official learning, which put importance on the hierarchic order and agriculture; on the other hand, they banned Kobunjigaku, (study of ancient rhetoric) and the Kogaku (learning about ancient teachings), which were popular learning at that time for corrupting public morals. Also, the lectures at Shoheizaka School (a governmental school), and the appointment examinations of the government officials adopted Neo-Confucianism only.
Some domain schools followed these examples, and as a result, some Confucians who had taught different leanings opposed to Neo-Confucianism lost many of their students and fell into great difficulty.
The five Confucians who opposed the Kansei Igaku no Kin (Bosai KAMEDA, Hokuzan YAMAMOTO, Taiho TSUKADA, Hoshu TOSHIMA, and Kakumei ICHIKAWA) were called Goki (five demons) of the Kansei era.
In Shoheizaka School, while the heterodox leanings were prohibited, learnings and lectures of Japanese heterodox schools were still allowed.