Ramen, soba and udon are the trinity of Japan's noodles, though it can sometimes feel as if the last one on that list is underappreciated. Ramen has followed sushi down the path of global domination — no doubt helped by instant ramen's popularity — and buckwheat soba noodles can swing from low to high, cooked by both no-frills neighborhood joints and haute cusine establishments. So where does this leave udon, a simple white noodle made with flour, salt and water?