The Sun and the Golden Rope / The Kid and the 31 Characters / Ushiwakamaru

A mother raises two sons alone after her husband dies. A boy at a temple hides two buns to give them to a kind family, but snow falls and he doesn't know where they are... The Tengu of Mt. Kurama gives Ushiwakamaru his father's sword, and trains him to become a great samurai. Source: crunchyroll