bottleneck slide
A guitar technique using a glass or metal tube on the finger to slide along the strings, producing a smooth, vocal-like portamento associated with blues and country.
In Depth
Slide guitar involves pressing a smooth, cylindrical object — traditionally a broken glass bottleneck, now usually a manufactured glass or metal tube — against the strings without pressing them to the fretboard. The slide can move freely along the string, producing continuous pitch changes (portamento) impossible with standard fretting. The technique originated in African American blues traditions, possibly influenced by West African one-stringed instruments like the diddley bow.
Robert Johnson, Elmore James, and Muddy Waters established slide guitar as a fundamental blues voice. Duane Allman (using a glass Coricidin medicine bottle) brought slide into rock with the Allman Brothers Band. Ry Cooder and Bonnie Raitt developed sophisticated acoustic slide styles. In country music, the steel guitar (played horizontally with a bar) evolved from the same technique. Open tunings (particularly open D and open G) are commonly used for slide playing because they allow full chords to ring when the slide lies flat across the strings.
Duane Allman discovered his signature slide tone using a glass Coricidin cold medicine bottle — the specific shape and glass thickness gave a tone so distinctive that vintage Coricidin bottles now sell for hundreds of dollars.