Bouzouki manner of a Neapolitan mandolins so as to increase the strength of the body to withstand thicker steel strings. The type of the instrument used in Rembetika music was a three-stringed instrument, but in the 1950s a four-string variety by Manolis Chiotis was introduced. From a construction point of view, the bouzouki can have differences not only in the number of strings but also in other features, e.g. neck length, width, height, depth of the bowl or main body, the width of the staves (the wooden gores or slices of the bowl) etc. These differences are determined by the manufacturer,
Bouzouki better suited to the kind of virtuoso playing he was famous for. Today, the tetrachordo is the most common bouzouki used in Greek music, though a few traditionalists still prefer the trichordo, particularly for the older "rebetika" style of playing. In addition to developing the modern tetrachordo bouzouki, Manolis Hiotis was a pioneer the use of amplification for the instrument, which he may have been using as early as 1945. However, the earliest documented use of amplification for the bouzouki comes from a 1952 photograph, showing Vasilis Tsitsanis and Yiannis Papaioannou playing bouzoukis, each with an electric guitar-style pick-up attached