Taste: black more bitter, white taste more delicate.

Color difference: because the black is the head side, buckwheat hulls are still inside, so black, more bitter. White is the second side, the color is close to white, but not all white, there are still black buckwheat hulls, but more fine, basically can not see, eat up basically no bitter taste.

Soba:

Soba (Japanese: buckwheat / soba? soba), is a Japanese food, similar to Chinese noodles, is made of buckwheat flour and water, and into a dough flattened and then cut thin noodles, boiled and eaten. In Japan, soba noodles can be eaten on many different occasions, not only at formal noodle shops, but also at small noodle stalls serving soba at train station platforms, as well as dried noodles and instant noodles sold in Polyjuice cups. More special occasions include eating soba noodles at the end of the year, celebrating longevity, and giving soba noodles to neighbors when moving to a new house.

Buckwheat is native to Central Asia and has been introduced to Japan in ancient times. Buckwheat is mostly produced in the alpine region, can grow in the barren land, like Japan's Nagano Prefecture, Yamanashi Prefecture are mountainous areas, barren land, not suitable for rice, so the two are Japan's buckwheat production areas. So there since ancient times, the habit of eating buckwheat.