The most important and iconic train line in Tokyo is the JR Yamanote Line. It is a circular loop that connects nearly all of the city's major urban centers and terminal stations, including Shinjuku, Shibuya, Tokyo Station, Ueno, and Shinagawa. The line is easily identified by its signature bright green (lime) color and its "inner" and "outer" circle designations. A full loop takes about 60 minutes, with trains arriving every 2 to 4 minutes during most of the day. Because it circles the "heart" of the city, it is the primary way most visitors and commuters navigate Tokyo. While the subway system is vast and complex, the Yamanote Line remains the "spine" of Tokyo's transit, serving as a vital landmark for understanding the city's geography.