Adim Chord on Ukulele
Adim = A – C – D# (Root, Minor 3rd, Tritone)
Adim stacks two minor thirds on top of each other — A up to C, C up to D# — producing a diminished triad with no perfect fifth at all, only a flatted, unstable one. On ukulele that translates to a genuinely stretched shape: index finger on the G string's second fret, middle finger on the C string's third fret, ring finger on the A string's third fret, and pinky reaching all the way to the E string's fifth fret, the highest single note among any of the A-family chords covered here.
Diminished chords are built entirely from symmetrical stacked minor thirds, which is what gives them their restless, unresolved quality — there's no stable perfect fifth anchoring the sound the way there is in a major or minor triad, so a diminished chord almost never functions as a place to land. Adim is used almost exclusively as a passing chord, most commonly as a vii° built on the leading tone of Bb major (where A is the seventh scale degree), connecting a I chord to a ii chord with a half-step of chromatic motion in the bass. It also appears as a secondary passing chord between A major and A#/Bb major shapes, since a diminished chord a half-step below a major chord creates smooth chromatic voice-leading into that chord's root. Because of the pinky's stretch up to the fifth fret, the chord also has a noticeably higher, thinner top note than the other A-family shapes, giving it a wiry, tense character even before considering its harmonic function.
Fingerings
Open Position
How to Practice It
This is the widest stretch in the set, so build it slowly: anchor the middle and ring fingers first, on the C string's third fret and A string's third fret respectively, since they sit close together, then add the index finger on the G string's second fret, and finally reach the pinky up to the E string's fifth fret last. If the pinky stretch feels unreachable at first, that's a normal early hurdle rather than a sign the shape is wrong — practice the reach in isolation, fretting just that one note cleanly before adding the other three. Because diminished chords are used briefly as connective tissue rather than chords to rest on, practice moving into and out of Adim quickly, from a neighboring major or minor chord, since that fast transition is the actual skill this shape is training.
Common Progressions
- vii°(of Bb) – ii – V – I, a chromatic passing move into Bb major (Adim – Cm – F7 – Bb)
- I – #Idim – ii (A – Adim – Bm, chromatic passing motion)
- Adim connects A major to A#/Bb major with smooth half-step bass motion.
- vi – vii° – I, a leading-tone approach in the key of Bb (Gm – Adim – Bb)
FAQ
- Why does Adim sound so unstable compared to A major or Am?
- It's built from two stacked minor thirds with no true perfect fifth, so there's no stable interval anchoring the chord — that symmetry is exactly what gives diminished chords their restless, unresolved quality.
- When would a ukulele arrangement actually use Adim?
- Almost always as a brief passing chord — commonly as the leading-tone vii° chord resolving into Bb major, or as chromatic connective tissue between A major and a neighboring A#/Bb chord.
- Why is the Adim shape harder than the other A-family chords?
- It needs a genuine stretch to the fifth fret with the pinky finger while three other fingers hold lower frets, making it the widest hand-span shape among these entries.
- Should Adim be strummed and held, like a I or IV chord?
- No — diminished chords are passing chords by nature, so the useful practice is moving quickly into and out of the shape rather than sustaining it the way you would a tonic chord.
Adim on other instruments: Adim on Guitar, Adim on Piano. Related: how chords are built, chord finder.