Soba is native Japanese noodles made of buckwheat flour or a mixture of buckwheat and wheat flour. They are about as thick as spaghetti and are served either hot or cold and with various toppings.
Tanuki Soba is a famous variant made of hot soba noodles in soup with tenkasu fried tempura batter bits. The topping is relatively simple, but that addition gives the dish a much richer flavor.