While many other music theory decks group chord symbols, often for multiple keys, with the rest of the music theory content to study, I wanted a deck that only taught the chord symbols. Used content mostly from those decks and Wikipedia articles about chords and chord names and symbols. The most scholarly "short" form of the symbol, from what I could discern as a novice, is on the front. The songbook that I regularly read uses that form, but I have added an alternate for the chords where that songbook uses a different symbol. The back contains the "long" form, name, description, component intervals, notes, treble clef representation, and audio.
The audio is not essential. However, the software used to create the staff images also can generate the audio. The audio might help to develop a sense of the general differences between the sounds of the chords.
One of the cards teaches the alignment of the component intervals to semitones. Remembering the alignment to the qualities of the higher intervals can be harder.
Because of only wanting to memorize the symbols rather than the notes for each chord in each key, chose C major as an overall representative key because its signature does not have sharps or flats. The accidentals for the thirds are for the C minor i chords because those chords are used instead of chords from the key of A minor.
Of the extended chords, only some variations are shown for the ninths. Even then, those variations are identical to the seventh chords extended by a major ninth. Only a flat ninth altered chord would give a minor ninth variation. Continuing with this simplification, the deck only contains cards with the dominant form of the eleventh and thirteenth extended chords. All of their forms are extended by the perfect eleventh or further by the major thirteenth. Other generalizations of some cards are mentioned in their descriptions.
