You surely know what are major chords, minor chords, seventh chords and diminished 7th chords ? But you may be wondering what half-diminished chords are ? In music, the most encountered chords are major and minor chords. These are the basis of the Harmony. Seventh chords (m7, Maj7 and dom7) are also widely used, particularly in jazz and blues music. When a guitar student start to take an interest in jazz, he can sometimes find chords with a little barbaric names such as diminished 7th chords, augmented or even half-diminished chords (m7b5). This article will explain you what are m7b5 chords, how to play them on the guitar and how to apply them in common harmonic contexts as major and minor II-V-I progressions.