Emperor Kōjin was the 57th emperor of Japan, reigning from 1142 to 1155. He was a member of the Yamato dynasty and is known for his relatively short reign during the Heian period. His era was marked by the increasing power of the samurai class and the decline of imperial authority. Kōjin's reign saw the continuation of cultural developments, including literature and art, characteristic of the Heian period. He was succeeded by his son, Emperor Go-Shirakawa, who would later play a significant role in the political landscape of Japan, further influencing the relationship between the imperial family and the samurai.