chromatic scale are played by barring all strings across a single fret. Open tunings are common in blues and folk music. These tunings are frequently used in the playing of slide and lap-slide ("Hawaiian") guitars, and Hawaiian slack key music. A musician who is well-known for using open tuning in his music is Ry Cooder, who uses open tunings when playing the slide guitar. Most modern music uses equal temperament because it facilitates the ability to play the guitar in any key—as compared to just intonation, which favors certain keys, and makes the other keys sound less in tune. Repetitive open-tunings are used for two classical non-Spanish guitars. For the English guitar, the open chord is C major (C–E–G–C–E–G); for the Russian guitar, which has seven strings, it is G major (D–G–B–D–G–B–D). When the open strings constitute a minor chord, the open tuning may sometimes be called a cross-note tuning. Major key tunings Major open-tunings give a major chord with the open strings. {| class="wikitable" |+ Open tunings |- ! !! Major triad !! Repetitive !! Overtones!! Other (often most popular) |- |Open A||(A,C,E)||A–C–E–A–C–E||A–A–E–A–C–E||E–A–C–E–A–E |- | Open B||(B,D,F)|| B–D–F–B–D–F ||B–B–F–B–D–F||B–F–B–F–B–D |- |Open C||(C,E,G)||C–E–G–C–E–G||C–C–G–C–E–G||C–G–C–G–C–E |- |Open D|| (D,F,A) || D–F–A–D–F–A || D–D–A–D–F–A|| D–A–D–F–A–D |- |Open E ||(E,G,B) ||E–G–B–E–G–B || E–E–B–E–G–B || E–B–E–G–B–E |- |Open F||(F,A,C)|| F–A–C–F–A–C || F–F–C–F–A–C ||C–F–C–F–A–F |- |Open G ||(G,B,D)|| G–B–D–G–B–D || G–G–D–G–B–D || D–G–D–G–B-D |} Open tunings often tune the lowest open note to C, D, or E and they often tune the highest open note to D or E; tuning down the open string from E to D or C avoids the risk of breaking strings, which is associated with tuning up strings. Open D The open D tuning (D–A–D–F–A–D), also called "Vestapol" tuning, is a common open tuning used by European and American/Western guitarists working with alternative tunings. The Allman Brothers instrumental "Little Martha" used an open-D tuning raised one half step, giving an open E♭ tuning with the same intervallic relationships as open D. Open C The English guitar used a repetitive open-C tuning (with distinct open notes C–E–G–C–E–G) that approximated a major-thirds tuning. This tuning is evident in William Ackerman's song "Townsend Shuffle", as well as by John Fahey for his tribute to Mississippi John Hurt. The C–C–G–C–E–G tuning uses some of the harmonic sequence (overtones) of the note C. This overtone-series tuning was modified by Mick Ralphs, who used a high C