In the event that Yoshitsugu was born under Yoshifusa, there is a popular story regarding the origin of his childhood name, Keimatsu (桂松 or 慶松). Before his son was born, Yoshifusa lamented his luck with children and wished for a male heir. One day, his wife decided to pray before a shrine dedicated to Hachiman Daibosetsu in their land. As she uttered her desires for a boy, a pine tree was cut before the shrine and fell before her. She plucked a portion of the fallen branches and ate it for good luck. When she gave birth, Yoshifusa was happy to see his first son. Grateful for the god's answer, he named his child after the plant.