Yukai (1345 - August 10, 1416) was a Shingon Sect priest scholar who lived from the Northern and Southern Courts period (Japan) to the mid-Muromachi period. His father is believed to have been FUJIWARA no Sanemitsu but this is not known for certain. His alias was Shogon. He was born in Kyoto.
At the age of 19, he ascended Mt. Koya where he studied Esoteric Buddhism under Shinko of Hosho-in Temple before taking over from his master as head of Hosho-in Temple in 1374.
He also studied under Koga of Ansho-ji Temple in Yamashina, Yamashiro Province (Kyoto City) where he learned the ways of the Anshoji School, and found achieved great success with his Esoteric Buddhist studies on Mt. Koya
Yukai's school was called Homon but this spilt into Chokaku's Jumon and Mt. Koya Esoteric Buddhism, and within the Shingon Sect were ranked with Raiyu of Negoro-ji Temple and Koho of To-ji Temple.
Yukai is known as the author of the "Hokyosho," a commentary on the Tachikawa School of Esoteric Buddhism.