The Japan Rail (JR) Pass covers all lines operated by the JR East company within Tokyo. The most famous and useful line for tourists is the Yamanote Line, a circular green line that connects major hubs like Shinjuku, Shibuya, Tokyo Station, and Ueno. Other covered routes include the Chuo-Sobu Line (yellow/orange) which cuts across the city, the Keihin-Tohoku Line (blue), and the Saikyo Line. It also covers the Narita Express (N'EX) for travel to and from the airport. However, it is vital to understand that the JR Pass does NOT cover the Tokyo Metro or Toei Subway lines, which make up a massive portion of the underground network. If you see a station marked with a "M" or a colorful circle logo, it is likely a private subway line where your JR Pass is invalid. To navigate these non-JR lines, most travelers use a Suica or Pasmo card alongside their JR Pass. This distinction is crucial for planning your daily itinerary to avoid unexpected out-of-pocket costs while exploring the city.