Compass Heart

The Compass Heart is an item unique to the Nintendo port of  Ultima III.

Description
The Stranger could receive compass hearts from Sherry of Britain, in exchange for bringing her flowers from the lost continent of Ambrosia. Using these artifacts, the hero could return to the gates of the Castle of Lord British at any time.

Trivia

 * An image-song, "Haato no Jishaku," (Magnet of the Heart) was created to promote  Ultima III for the NES in Japan.