Open tunings may be "chordal" or "modal". In chordal open tunings, the base chord consists of at least three different pitch classes, and may include all the strings or a subset. The tuning is named for the base chord when played open, typically a major chord, and all similar chords in the 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.