Technically, the Yamanote line is only the stretch running from Tabata to Shinagawa. The reason is that, historically, Yamanote was the name given to the land west of the Imperial Palace and when it was inaugurated, in 1885, the railway was located approximately on the line separating the Yamanote and Shitamachi areas. The full Yamanote loop was completed in 1925 and today it includes 29 stations, with the last one added in 1971, the Nishi-Nippori.
However, I just learned today that a new project was started, which will add to the line the 30th station, located between Shinagawa and Tamachi. The new station, planned for 2013, will be located approx. 1 kilometer away from Shinagawa (the distance between Shinagawa and Tamachi is 2.2 kilometers) and it will be part of a new office and commercial development.
EXIF info:
Nikon D90
Lens: 8-16mm F/4.5-5.6G
Focal Length: 16mm
Aperture: F/5.6
Shutter Speed: 1/500s
ISO Sensitivity: ISO 200