In time, the Japanese cooks developed a wide variety of soba recipes, categorized by the type of flour used: 100% buckwheat, 80% buckwheat plus 20% wheat flour, or more sophisticated versions with traditional Japanese green tea (matcha) or powdered cherry blossoms added to the mix of flour. Soba can also be categorized by how it is served, hot or cold, and by the ingredients used, like eggs, nori seaweeds, spring onions, shiitake mushrooms, fried tofu cheese or tempura. Actually, you can add almost anything to soba.
My favorite? That would be the kikouchi soba, a type made only from buckwheat flour, served cold, with two types of dipping sauce (soba tsuyu) and with a tsukemono (Japanese pickles) garnish:
EXIF info:
Nikon D90
Lens: VR 18-55mm F/3.5-5.6G
Focal Length: 18mm
Aperture: F/5
Shutter Speed: 1/40s
ISO Sensitivity: ISO 1000