Article: Most songs in Western music are built around a set of common chord progressions, built on the diatonic scale. Once you know which progressions are most common in the music you listen to, you’ll have a much easier time identifying them in songs you want to learn.  Diatonic chords are numbered with Roman numerals according to the position of the root note on the scale. For example, the I chord on the C major scale is the C tonic chord (C-E-G), consisting of the 1st, 3rd, and 5th notes of the C major scale. Minor chords are written with lower case Roman numerals (e.g., i, ii, iv, etc.). One of the most common chord progressions in Western popular music is I-IV-V-I. Try playing common chords and really paying attention to what they sound like. Don’t just stick to root positions (where the notes played are the 1st, 3rd, and 5th notes, or scale degrees, of the key)—practice listening to inversions, too (such as 3rd, 5th, 8th). Listen to 7th, diminished, and augmented chords as well as basic major and minor triads. The more you listen to the chords, the more familiar they will become.  For example, in C Major, the root notes are C, E, and G, while E, G, and C, are the 3rd, 5th, and 8th scale degrees, respectively, of the first inversion of C. Try quizzing yourself with a chord identification tool like this one: https://tonedear.com/ear-training/chord-identification Songs written in major keys tend to sound bright, upbeat, happy, or hopeful, while minor keys lend a gloomy, sad, or scary sound. The easiest way to determine whether a song is major or minor is simply to listen to the overall “mood” of the piece. While the chords in a minor key song will primarily be minor chords, there will likely be some major chords mixed in. The reverse is also true of major key songs. Once you’ve figured out the tonic chord, you will have a good foundation for figuring out the rest of the song. Most songs end on the tonic (I) chord, and many also begin there. The tonic chord should be the predominant chord throughout the song, and hearing it will give you a sense of completion or satisfaction. For example, “Twinkle Twinkle Little Star,” when played in the key of C major, begins and ends on a C major tonic chord. In most songs, the bass line is the harmonic accompaniment to the melody. The bass line tends to be built on the root notes of each chord in the song. This means that if you can figure out the notes of the bass “melody,” you can pinpoint the root of each chord and build from there.  For example, if you are listening to “Twinkle Twinkle Little Star” in C major, you may identify the notes C, F, C, F, C, G, C in the bass line of the first 4 measures. These are the root notes of the chords for those measures. Once you’ve figured out the root notes, ask yourself about the quality of each chord. Does it sound major or minor? Do you hear tones other than the 1st, 3rd, and 5th notes of the chord (e.g., the 7th)? After you’ve figured out the chords, play them in order, following the rhythm of the piece. You may find it helpful to play along with a recording of the song to make sure that you have the timing right. Depending on the type of instrument you’re playing, this could mean playing the different parts together or playing the chords as accompaniment to a voice or a second instrument. Run through the song several times to make sure that your chord changes are timed correctly with the melody. For example, if you are playing the piano, you will probably play the chords primarily with your left hand while your right hand carries the melody.

What is a summary?
Familiarize yourself with common chord progressions in your genre. Practice identifying chords by sound. Determine whether the song is in a major or minor key. Identify the tonic (I) chord. Use the bass line as a guide to find other chords. Practice playing the chords in sequence. Put the chords and melody together.