Botamochi are a springtime treat made with sweet rice and sweet azuki (red bean) paste. They are made by soaking sweet rice for approximately six hours. The rice is then cooked, and a thick azuki paste is hand-packed around pre-formed balls of rice.
A very similar treat, ohagi, uses a slightly different texture of azuki paste, but is otherwise almost identical. It is made in autumn. Some recipe variations in both cases call for a coating of soy flour to be applied to the botamochi/ohagi after the azuki paste.
The two different names are derived from the Botan (peony) which blooms in the spring and the Hagi (Japanese bush clover or Lespedeza) which blooms during autumn.
Ohagi is named after the bush clover (hagi), which flowers during autumn. Botamochi is the modern name for the dish "Kaimochi" mentioned in the Heian Period text Ujishui Monogatari (宇治拾遺物語).