I. Intro to Chords

II. Triads and Inversions

III. Sus Chords

IV. Sixth Chords

V. Seventh Chords

VI. Extensions

VII. Add chords and Alterations

VIII. Bass and Polychords

IX. Modern and Chromatic Chords



Part I: Intro to Chords

A chord in simplest terms is a set of 2 or more tones played together simultaneously. By far the most basic chords that most students of music learn are triads, or chords with 3 tones formed by the tonic, mediant, and dominant of a specific scale (if the scale is more or less than 7 tones then it’s simply the 1, 3, and 5 tones of the scale). They are also formed another way dealing with specific intervals (now would be a good time to review lesson I of the scales section). Usually 2 toned intervals are not always considered chords; chords by definition have to be 3 or more notes, however you will hear the perfect fifth and perfect fourth occasionally referred to as chords (quite often in rock music as the “power chord” or "inverted power chord" respectively).


You should note that until section X there is little or no explanation of how to use the chords in musical composition or classical music theory. The previous sections simply introduce all the terminology used when describing a chord. For the time being, section X will only describe chord progressions in terms of classical music theory. For this reason, you do not need to read lessons VI, VII, or IX beforehand (though it is suggested you at least look over them). Classical theory does not generally use many extended chords, polychords, or alterations of any kind but there is an important emphasis on bass chords, especially in inversions.