Mensho Tokyo SF
Look for the lines on busy Geary Street where Union Square blurs into the edges of the Tenderloin and you'll find what eager ramen fans consider the city's best bowl. This was the first U.S. outpost of a prominent Tokyo-based ramen shop, and the quality and consistency of its noodles and broths continue to be spectacular. The decor on the walls is primarily a series of graphics explaining the scientific aspects of ramen; if you want a doctorate in ramen, this is a good place to start.