Prepare the vegetables: This is easier in a food processor than by hand. If using a food processor, shred the cabbage and sprouts with the slicing disk, then grate the carrots using the grating disk. Or use a chef's knife to chop the cabbage and sprouts into thin strips, then coarsely grate the carrots.
Cook the soba noodles: bring a large pot of water to boil and cook the noodles according to package directions. Drain and rinse with cold water before returning to pot.