The 3rd bridge is a term used on guitars such as the Fender Jazzmaster that has the strings continue through to the tremolo piece. The Fender Jazzmaster is an Electric guitar that was first introduced at the 1958 NAMM Show and was designed as a more upmarket instrument than the A string is the vibrating element that is the source of vibration in String instruments such as the Guitar, Harp, Piano, and members It is called the 3rd Bridge because some players utilized the unique sound that one can get out of playing in that area. Bands like Sonic Youth and Placebo are known for using this technique. Sonic Youth is an American Alternative rock band formed in New York City in 1981 Placebo are an Alternative rock band formed in London in 1994 currently comprising Brian Molko, Stefan Olsdal and Steve Forrest