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C DiminishedThe C Diminished chord is a three-note chord made up of C, E♭, and G♭.
Piano chords, scales, theory & ear training
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Full identifier ›Today at the piano
Thursday, July 30, 2026.
On this day
1751 Maria Anna Mozart, called Nannerl, a keyboard prodigy who toured Europe with her brother, was born in Salzburg.
Term of the day
Half-Whole Diminished ScaleThe half-whole diminished scale is the mirror image of the whole-half diminished, an eight-note octatonic scale that alternates half steps and whole steps.
Did you know
Pianos are typically tuned so the A above middle C sounds at 440 Hz, the standard called A440.
Piano by the numbers ›Jump to any reference page
Chords, scales, and modes — every key, both enharmonic spellings.
The index
Look anything up directly, in both enharmonic spellings, C♯ and D♭ alike.
Learn and practice
The reference is for looking things up; these are for getting better.
Learn Piano: the step-by-step pathAn ordered course from your first notes through chords, scales and theory — no login required. Start here.Follow the pathChord FinderPlay or click any combination of notes and see what chord it makes.Open the toolChord and Scale MasteryGuided series that read like short books, from what is a chord to altered harmony.Start readingPractice RoomConnect a MIDI keyboard and get graded feedback on timing, evenness and accuracy.Enter the roomCircle of FifthsThe interactive wheel: keys, relatives, and how they connect.Explore it
Who writes this
Maintained on nights and weekends by Justin Evans, a pianist of 25 years. Report a mistake