As for why Yoshitsugu changed his mind, the reasons remain an enigma to this day. No one really knows why Yoshitsugu did it since little is recorded for it. There are many tales made for why he could have, but they lack any real backing due to the absence of historical evidence. The popular scenario was developed during the Edo Period, stating he joined out of friendship. In this interpretation, Yoshitsugu was only thinking of joining Ieyasu and was asked three times by Mitsunari to join him. Although Yoshitsugu knew it was a failing cause, he couldn't abandon his ties for his friend and merged his forces into the Western army with his sons. Yet another story states Sanada Masayuki's wife was being held hostage by the Western army. Tied to the Sanada family due to his daughter's marriage, he was forced into the hands of the opposition for her safety. Another fable depicts that he conflicted with Ukita Hideie and was joining Ieyasu just to avoid him. Mitsunari heard of this and played mediator between the two parties, eventually convincing Yoshitsugu to stay.