Shikken

The Shikken (執権, しっけん^?) was a titular post, officially a Regent of the Shogunate, from 1199-1333, or during the Kamakura era, therefore it was head of the bakufu (Shogunate). It was part of the era referred to as Regent Rule 執権政治 (Shikken Seiji^?).

During roughly the first half of that period, the Shikken was the de facto military dictator of Japan (not including the independent Northern Fujiwara). The title of Shikken was modified, as second in command to the Tokuso beginning in 1256, but by the Muromachi period (1333-1573) the position, though not abolished, did not even figure into the top ranks. The position ceased to exist after the Muromachi period.

The word shikken derives from kanji characters 執 and 権 literally meaning taking authority.

Though officially a Regent for the Shogun in the Kamakura shogunate in Japan, on paper a Shikken derived power from the shogun, in reality the actual shogun had been reduced to a figurehead in a similar marginalizing manner just as the emperor and imperial court earlier had been reduced to figureheads by the shogun. Both the posts of Shikken and Tokuso were monopolized by the Hōjō clan.

Hōjō Tokimasa, who was the father-in-law of the first shogun Minamoto no Yoritomo, father of Hōjō Masako, became the first shikken in 1203, after Yoritomo's death. The shikken was the chief of the mandokoro at that time. Tokimasa became the de facto ruler of the shogunate (Japan) by monopolizing decisions for the young shoguns Minamoto no Yoriie and Minamoto no Sanetomo, executing whoever got in his way, family or not. Tokimasa's own grandson Minamoto no Yoriie and great grandson were murdered on Tokimasa's orders, a year after he replaced the second shogun Minamoto no Yoriie with Sanetomo.

...
Wikipedia