Soba noodles are made from buckwheat flour.
some soba is made with buckwheat only. it is called juwari soba.
juwari soba is made with 100% buckwheat flour. some soba contains wheat flour. juwari soba tastes strong and nutty.
some soba is made with eighty percent buckwheat and twenty percent wheat flour. it is called nihachi-soba.