Special orders don't upset them at Katana-Ya, a tiny noodle shop that looks like it was transported whole from the Ginza to its location a few blocks from Union Square. In addition to choosing different broths (beef, pork, or chicken, each seasoned with miso, salt, or soy sauce), you can ask for the noodles to be cooked hard or soft, and assemble toppings differently from those appearing on the menu (barbecue pork, fried chicken, roast pork, tofu, kimchi, greens in varying combinations). There are other items available (sushi, the rice bowls known as donburi), but ramen is definitely the place's specialty. Open for lunch, dinner, and, amazingly for San Francisco, late supper — until 2 a.m. most nights. Happy will be the downtown tourist, shopper, or theatergoer who slurps down a comforting bowlful for well under $10.