buckwheat flour
Flour ground from buckwheat, used primarily for making soba noodles and other buckwheat-based foods.
I make handmade soba noodles with buckwheat flour.
Refers to buckwheat noodles or the buckwheat plant itself, whereas そば粉 is the flour.
Standard kanji-kana mixed spelling.
Full kanji spelling; less common but still seen.
Compound of そば (buckwheat) and 粉 (flour). The reading そばこ is a straightforward combination of the two elements.