Translation of "Buckwheat" in Japanese

There is a custom of eating buckwheat noodles on New Year's Eve in Japan.

日本では大晦日に蕎麦を食べる習慣があります。

Soba is made of buckwheat flour, and udon and kishimen are made of plain wheat flour.

そばはそば粉から、うどんやきしめんは普通の小麦粉からできてるの。