From China Digital Space
dāngjīn huángshang 当今皇上
Allusion to the sitting president of China in general, and at present to Xi Jinping. Implies that the head of state was anointed, not elected, to a position far more powerful than "president."
In a September 2014 speech, Xi Jinping touted "consultative democracy" as a way for Chinese citizens to participate in government without elections.
CDT first detected that "reigning emperor" was blocked from Weibo search results on August 21, 2014. It remains blocked as of May 7, 2015.
Example of "reigning emperor":
Yushenghai (@余胜海): Crazy "Steamed Buns": Ever since Daddy Xi ate at Qingfeng Steamed Buns on Yuetan North Road, this classic capital restaurant has become a national sensation. Demand has outstripped supply for pork buns and stir-fried liver. Yesterday's everyday buns have become today's tribute to the reigning emperor. (January 24, 2014)
See also heir apparent.