In this article, you’ll learn how to construct the A diminished triad as well as how to play it on piano and guitar.
We’ve also included sections on inversions for those that want a deeper understanding. Lastly, listen to some examples of popular songs that featured this triad.
Root, 3rd and 5th
The A dim triad is formed of the 1st, flat 3rd and flat 5th of the A major scale.
- A – root note
- C – Minor 3rd above the root
- Eb – diminished 5th above the root
Here is the triad written on the stave in the treble and bas clef.
Before you read on make sure that you have a basic understanding of intervals. Intervals are vital for understanding how triads are built. Check out our guide to major, minor and perfect intervals for more on this.
A diminished Chord on Piano
Below you can see how to play this triad on the keyboard or piano. This pattern of notes could also be played starting on any A note.
However, the order of the notes must be the same:
- A – lowest note
- C – middle note
- Eb – highest note
This is called ‘root position’.
A dim Triad on Guitar
There are two simple positions that you can use to play an A dim chord on guitar. Both positions can also be slide up or down the neck to play different diminished triads.
A 1st inversion is where we take a triad but we start on the second note, which in this case is C natural. We still keep the E flat above, but then the A (or root) become the highest note.
- C – min 3rd (lowest note)
- Eb – dim 5th (middle note)
- A – root note (highest note)
1st inversion on Piano
On the piano we can play the 1st inversion of an A dim triad by starting on a C natural. They play the Eb above and the A above this.
1st Inversion of Guitar
Below are the most common shapes for playing an A diminished triad in the 1st inversion. Remember that we can only use certain shapes are the pitches of the three notes are important.
A 2nd inversion is where we take a triad but we start on the third note, which in this case is E flat. We still keep the A above this as we did from the 1st inversion. Then the C becomes the highest note in the chord.
- Eb – dim 5th (lowest note)
- A – root note (middle note)
- C – min 3rd (highest note)
2nd inversion on Piano
On the piano we can play the 2nd inversion of an A diminished chord by starting on a E natural. They play the A above and the C above this.
2nd Inversion of Guitar
Below are the most common shapes for playing an A dim triad in the 2nd inversion. Remember that we can only use certain shapes are the pitches of the three notes are important.
Keys that Include A Diminished Triad
You might be asking – what key do you find A dim triad in? Well, as you can see below, A Dim is the second chord in the key of G minor.
It is also the 7th chord in the key of Bb Major.