What is Open A tuning?

Open A tuning is E-A-E-A-C#-E (low to high). Strumming all strings produces an A major chord. It's structurally the same as Open G but one whole step higher.

Is Open A the same as Open G with a capo?

Yes, musically they are identical — Open G with a capo at fret 2 gives you the same pitches as Open A. Many players use this approach. Without a capo, Open A has higher string tension which some slide players prefer for better control.

What scales work in Open A?

The A major pentatonic and A blues scale are natural choices. A Mixolydian gives a bluesy feel, and the A major scale works for country and folk styles.

C Diminished Guitar Scale

Guitar scale in Open A tuning — fretboard diagram

Tuning

Frets

C Diminished in Open A — Notes and Intervals

The C Diminished scale, also known as the Octatonic scale and Messiaen's Mode of Limited Transposition #2, alternates whole and half steps to create an 8-note symmetrical structure. On Guitar, its notes are C, D, Eb, F, Gb, Ab, A, B. Only three unique diminished scales exist — after three transpositions, the notes repeat. It is the definitive sound of film noir, thrillers, and psychological horror, used by composers from Stravinsky to Hans Zimmer to evoke dread, ambiguity, and mounting tension. Use it over dim7 chords and as a sophisticated tension device over dominant 7ths. Commonly used in Jazz, Film Scores, Classical, Metal. Notable players include Django Reinhardt, Joe Pass, Bela Bartok, Dream Theater. Use over dim7 chords and as a tension device over dominant 7ths. Each diminished scale works over 4 different root notes (every minor 3rd).

Notes: C, D, Eb, F, Gb, Ab, A, B

Intervals: 1P, 2M, 3m, 4P, 5d, 6m, 6M, 7M

Degrees: 1 2 b3 4 5 b6 7 8

Formula: W-H-W-H-W-H-W-H

Number of notes: 8

Tuning: Open A (E-A-E-A-C#-E)

Also known as: whole-half diminished

About Open A Tuning

Open A tuning (E-A-E-A-C#-E) produces an A major chord when strummed open. It is structurally identical to Open G tuned up one whole step, delivering a brighter, more tense sound that works particularly well for slide guitar centered on the key of A.

Jimmy Page used Open A with a slide on Led Zeppelin's 'In My Time of Dying' from Physical Graffiti (1975). Rory Gallagher also employed Open A for his raw, energetic slide work. Many players achieve Open A by simply placing a capo at the 2nd fret in Open G tuning, which is why dedicated Open A usage is less commonly discussed. However, without a capo, Open A gives direct access to the open A string resonance and a different feel under the fingers due to the higher tension.

BluesSlide GuitarRockDelta Blues

Notable artists: Jimmy Page, Rory Gallagher, Delta blues players

Best for: Slide guitar in the key of A, blues playing, and situations where you need the brightness of Open G tuned up without a capo

Musical Character

TenseDreadfulAmbiguousSuspenseful

Alternates whole-half steps, creating an 8-note symmetric scale. Only 3 diminished scales exist — after 3 transpositions, you get the same notes. The definitive sound of suspense and film noir.

Chord Progressions Using This Scale

I – ♯I°7 – ii – V (Diminished Cliché)Jazz / Soul — Nostalgic & Vintage

Explore This Scale in Other Tunings

← All Guitar scales in Open A tuning