Hasekura Rokuemon Tsunenaga was a kirishitan Japanese samurai and retainer of Date Masamune, the daimyō of Sendai. He was of Japanese imperial descent with ancestral ties to Emperor Kanmu.

In the years 1613 through 1620, Hasekura headed the Keichō Embassy, a diplomatic mission to Pope Paul V. He visited New Spain and various other ports-of-call in Europe on the way. On the return trip, Hasekura and his companions re-traced their route across New Spain in 1619, sailing from Acapulco for Manila, and then sailing north to Japan in 1620. He is considered the first Japanese ambassador in the Americas and in Spain, despite other less well-known and less well-documented missions preceding his mission.

Although Hasekura's embassy was cordially received in Spain and Rome, it happened at a time when Japan was moving toward the suppression of Christianity. European monarchs refused the trade agreements Hasekura had been seeking. He returned to Japan in 1620 and died of illness a year later, his embassy seemingly ending with few results in an increasingly isolationist Japan. Japan's next embassy to Europe would not occur until more than 200 years later, following two centuries of isolation, with the "First Japanese Embassy to Europe" in 1862.