The Ko-kyo movement by Ko Yui (Kang Youwei) which preached that the name of eras should be abolished and a Confucian calendar should be used, was a threat to the traditional system, and was considered dangerous by the Qing Dynasty, resulting in the ban of "The Rediscovered Versions of the Confucian Classics."
康有為の孔教運動は年号を廃して孔子紀年を用いることを主張するなど従来の体制を脅かすものであったため、清朝から危険視され『孔子改制考』は発禁処分を受けた。