Nichiji (日持; February 10, 1250 – after 1304), also known as Kaikō, was a Buddhist disciple of Nichiren who traveled to Hokkaido, Siberia, and China.
Nichiji was born in Suruga Province, the second child of a large and powerful family. At first he studied to become a Tendai priest but soon he joined Nichiren as one of his initial followers.
Nichiji was one of the "six chosen disciples" of Nichiren, but was also a disciple of Nikkō. After Nichiren died in 1282, Nichiji established Eishō-ji, now Ren'ei-ji (蓮永寺) in Shizuoka. But soon, relations with Nikkō became strained. He set out on a missionary journey on January 1, 1295. His plan was to walk to Hakodate, Hokkaidō and from there proceed to Xanadu in order to convert the Mongols.
For many centuries it was unknown what happened to Nichiji after he left Japan. According to legend, he founded a temple in northern Japan and caught a new fish in Hokkaido that he named hokke, after the Lotus Sutra; even in legends it was unclear if