On the mandolin, the C#aug chord is the augmented chord built from C#, F, A. Its first mandolin voicing is the movable voicing: G string at fret 6 (ring finger); D string at fret 3 (index finger); A string open; E string at fret 5 (middle finger). Keep this page open while you practise: it lists the notes, every practical voicing, the mistakes that make it sound wrong and the progressions where it does its best work.
What notes are in the C#aug chord?
The C#aug chord is a augmented chord, and its notes are fixed: C#, F, A. Every voicing on every instrument uses these same notes, in some order and in some octave — change one of them and you are playing a different chord. The table below lists each note with its interval from the root C#, so you can see the structure of C#aug at a glance. On the mandolin, the movable voicing of C#aug puts those notes under your fingers in the order the fingering lists them.
| Note | Interval |
|---|---|
| C# | Root |
| F | 3 |
| A | #5 |
The root is C#, the note the chord is named after and the note your ear hears as home. Above it, the intervals in C#aug are 3, #5. That combination is what makes C#aug sound the way it does: the intervals decide the colour, and the root decides the pitch. On the mandolin, the notes appear in the order the fingering dictates, but the set of notes never changes.
C#aug sounds exotic and tense, the sound of a chord that can resolve in several directions at once. Listen for that character when you play it — if C#aug does not sound that way, one of the notes is probably wrong, and the table above is the place to check. On the mandolin, the movable voicing of C#aug puts those notes under your fingers in the order the fingering lists them.
Comparing C#aug with its closest relatives helps to fix it in your ear. In short, augmented against major: both have the major 3rd F, but C#aug raises the 5th to A instead of the perfect 5th G#, and that one change removes the chord's sense of home. Hearing the comparison matters more than reading it: play C#aug, then play the chord it is compared with above, and let your ear find the note that changed. On the mandolin, start with the first voicing above and listen for the notes C#, F, A in C#aug.
How to play C#aug on mandolin
On the mandolin, C#aug has 3 voicings in the data below, and each one uses the same notes — C#, F, A — in a different place on the neck. There are 3 voicings listed for C#aug on the mandolin; learn the first, then add the others as you need them. Finger numbers below use 1 for the index finger, 2 for the middle finger, 3 for the ring finger and 4 for the little finger, and x means the string is not played.
Another way to play C#aug is the movable voicing, in around fret 3: G string at fret 6 (ring finger); D string at fret 3 (index finger); A string open; E string at fret 5 (middle finger). The stretch is the challenge: the fretted notes span from fret 3 to fret 6, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in C#aug — C#, F, A — sounds, with no buzz and no accidental open string.
The movable voicing puts C#aug in around fret 3: G string at fret 6 (little finger); D string at fret 3 (index finger); A string at fret 4 (middle finger); E string at fret 5 (ring finger). The stretch is the challenge: the fretted notes span from fret 3 to fret 6, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in C#aug — C#, F, A — sounds, with no buzz and no accidental open string.
The open position is the voicing to learn if you want C#aug in open position: G string at fret 2 (middle finger); D string at fret 3 (ring finger); A string at fret 4 (little finger); E string at fret 1 (index finger). The stretch is the challenge: the fretted notes span from fret 1 to fret 4, so keep your thumb low behind the neck and let your fingers reach rather than squeezing the neck. Strum or pluck it slowly first and check that every note in C#aug — C#, F, A — sounds, with no buzz and no accidental open string.
Choosing between the voicings of C#aug is a musical decision, not a right-or-wrong one. The open or low-position voicing rings the most and suits strumming, while a barre or movable voicing lets you slide C#aug up the neck to any key without changing the shape. When you change chords, pick the voicing of C#aug that sits closest to the chord before it — shorter moves between shapes mean faster, cleaner changes. Practise the change into C#aug from the chord that comes before it in your song, not the chord on its own, because the move is the skill. On the mandolin, the movable voicing of C#aug puts those notes under your fingers in the order the fingering lists them.
A short practice routine for C#aug on the mandolin: play the first voicing four times slowly, checking each note, then change to it from the chord a fourth above C# and back, four times, at a slow tempo. Then play the second voicing the same way. If a note buzzes, stop and fix the finger placement rather than playing through the buzz — clean notes at a slow tempo become clean notes at full tempo, while buzzes practised fast become habits. Use the Mandolin Chord Finder to see the diagram for C#aug while you practise, and the Chord Finder to compare it with the same chord on other instruments.
Common mistakes
These are the mistakes that most often make C#aug sound wrong on the mandolin, and each one has a concrete fix. Work through them one at a time rather than trying to fix everything at once.
Playing a perfect 5th. If the 5th is G# the chord is just major. The sharpened 5th A is the whole point of the augmented chord. On the mandolin, the movable voicing of C#aug puts those notes under your fingers in the order the fingering lists them.
Sitting on it too long. C#aug is a passing colour, not a home chord. Hold it for a beat or two, then move on — it sounds stranger the longer it lasts. On the mandolin, the movable voicing voicing is the place to hear it in C#aug.
Resolving it nowhere. Because it is symmetrical, C#aug can resolve in several directions, but it must resolve somewhere. Pick a destination chord and practise the move. On the mandolin, the movable voicing of C#aug puts those notes under your fingers in the order the fingering lists them.
Confusing it with a whole-tone sound. The augmented triad is part of the whole-tone scale, but on its own it is just three notes: C#, F, A. Do not add extra whole-tone notes unless you mean to. On the mandolin, the movable voicing of C#aug puts those notes under your fingers in the order the fingering lists them.
Where C#aug is used
C#aug is not a diatonic triad in any major or minor key, because it is an extended or altered chord, but its base triad belongs to the key of C# major, the key of F# major, the key of G# major. a passing chord that creates chromatic lift, often between a major chord and its IV. As a dominant-type chord it also points toward F# major, the key a perfect fourth above C#, which is the tonic it most often resolves to. That is where C#aug does its work: not as a home chord, but as a chord that creates movement and then resolves. On the mandolin, the movable voicing voicing is the place to hear it in C#aug.
Because C#aug is an extended or altered chord, it appears in progressions as a colour or a dominant rather than as a diatonic staple. Try it in place of the plain C# triad in a progression you already know, and listen to how the extra notes change the feel — that substitution is the usual way extended chords enter real music. The Chord Progression Builder lets you try C#aug in a progression in any key and hear how it connects to the chords around it. On the mandolin, start with the first voicing above and listen for the notes C#, F, A in C#aug.
The same chord on other instruments is covered in C#aug on guitar, C#aug on piano, C#aug on ukulele, and the scales that fit over it are the C# major scale and the C# minor pentatonic scale. Learning C#aug on the mandolin and then checking it on another instrument is one of the best ways to fix the notes — C#, F, A — in your memory, because the notes stay the same while everything else changes.
Practising C#aug
A short worked example makes C#aug concrete. Play the four-chord progression F# – C# – D#m – B in F# major, the key C#aug most often resolves toward: F# – C# – D#m – B. Play each chord for one bar at a slow tempo, and listen to how C#aug sounds in that sequence — whether it feels like home, like a lift, or like a chord on its way somewhere else. Then play the same four chords in a different order, starting on C#aug itself, and notice how its character changes when it opens the progression instead of sitting inside it. On the mandolin, start with the first voicing above and listen for the notes C#, F, A in C#aug.
For a second exercise, play C#aug and then the chord a fourth above C#, back and forth, four times each. That move — a chord and the chord a fourth above it — is the most common resolution in Western music, and it is the move C#aug is built for when it acts as a dominant. Finish by playing C#aug on its own, slowly, and naming each note out loud as you play it: C#, F, A. Naming the notes while you play them is what turns a shape into knowledge you can use in any key. Test yourself with the Practice Chord Quiz and keep time with the Metronome as the tempo rises. On the mandolin, start with the first voicing above and listen for the notes C#, F, A in C#aug.
Frequently asked questions
Why does C#aug sound strange?
Its 5th is sharpened to A, so the chord is two major 3rds stacked and divides the octave into three equal parts. With no perfect 5th to anchor it, the chord sounds like it floats. On the mandolin, check the first voicing above for that note.
What notes are in C#aug?
C#aug contains C#, F, A: the root C#, the major 3rd F and the augmented 5th A. The raised 5th is the note that makes it augmented. On the mandolin, check the first voicing above for that note.
Where is C#aug used?
As a passing chord between a major chord and the chord a semitone above it, and as an altered dominant in jazz. It is a colour chord, used briefly for lift and surprise. On the mandolin, check the first voicing above for that note.
How do you play C#aug on the mandolin?
The first voicing is the movable voicing: frets 6–3–0–5, fingers 3–1–0–2, on the mandolin. That voicing uses the notes C#, F, A, and it is the one to learn first. The page above lists more voicings for C#aug, so you can choose the shape nearest the chords around it.
Is C#aug hard to play on the mandolin?
It depends on the voicing. The first voicing of C#aug on the mandolin is the easiest starting point, and the movable voicings further up the neck are harder because they need a barre or a wider stretch. Practise the first voicing cleanly at a slow tempo before you try the others, and the harder shapes will come more easily.