Learning how to read "Block" chords.
It's easier than you think.
One of the easiest ways to explain or write-out chords quickly is by using the “Block Diagram”. If you've been playing guitar for a while and building your chord vocabulary; and you are relative familiar with most of the note names and locations on the fretboard - eventually, it stands to reason that writing-out finger locations on a fretboard diagrams might NOT always be the only way to communicate chord structures. I use the following method with many of my students, as it is quick and easy to do.
Universally speaking, the understanding is that we read chord structures from left to right - from the sixth string to the first string. [ E - A - D - G - B - E ] The reason for this is because of the structure of the chord itself. Most (but not all) chords are built from the lowest note to the highest note.
We need to think in terms of the actual location of the note on the fretboard for this lesson.
For example: If I say, "string 6, fret 3” - which note is that? If you answered "G", then you are correct.
If I say, "string 4, fret 5", what is that note? The answer is also "G", but one octave higher.
Here's the thing - The names of the notes are NOT the primary focus for this lesson.
If I tell you that a very common chord (you probably already know), looks like this: 3-2-0-0-3-3, which chord do you think that it is? What do those numbers indicate? Do they indicate the fingers? Maybe they indicate the frets. Maybe they indicate the fret numbers on the strings. Which one do you think is the correct answer?
What we're looking at is the block diagram of the common open-string "G" major chord: "3-2-0-0-3-3". Each number reads left to right as the fret placement on the string position in order. In other words the first "3" indicates the 3rd fret of string 6. The "2" indicates the 2nd fret of string 5, and so on.
Here are a few more examples:
x-3-2-0-1-0 is the open string "C" chord.
Notice, there is an "x" in that structure. What do you think it means? If "0" means "open-string", what does the "x" indicate? If you answered "You do not play that string.", then you are correct.
x-x-0-2-3-2 is "D"
x-0-2-2-1-0 is "Am"
0-2-2-0-0-0 is "Em"
x-0-2-2-2-0 is "A"
The idea behind this lesson is to find the notes on the strings and the frets indicated by their position in the structure. If you are a beginner guitarist, this might take some research to find out which fingers are used for each note. If you are someone who has been playing a while, you can probably figure out where your fingers go with ease.
Barre chords
Let's try some Barre chord structures using this method.
1-3-3-2-1-1 or x-3-3-2-1-1 is the "F" chord, otherwise known as the most-hated chord for beginner guitarists. Why? Because two of the notes are "barred". Some beginners struggle with the "F" chord for a while, because it requires pushing down twice as hard to get two notes with your first finger, and this can be a little uncomfortable.
Let's try another one.
3-5-5-4-3-3 is the barred "G" chord.
x-3-5-5-5-3 is the barred "C" chord.
Thinking and communicating these types of structures will help you better understand chords and how they are built. It will also help you quickly know and understand the locations of all of the chords in your vocabulary.
Here are a few more examples:
x-3-2-0-0-0 is the "C Major 7" chord.
x-3-2-3-1-0 is the "C (dominant) 7" chord.
x-x-0-2-2-2 is the "D Major 7" chord.
x-x-0-2-1-2 is the "D (dominant) 7" chord.
Notice how similar in structure those chords are? Sometimes, you just need to change one note in a chord structure to name a completely different type of chord.
0-2-2-1-0-0 is the "E" chord.
0-2-0-1-0-0 is the "E (dominant) 7" chord.
0-2-2-0-3-3 is the "E minor 7" chord.
x-0-2-1-2-0 is the "A Major 7" chord.
x-0-2-0-2-0 is the "A (dominant) 7" chord.
I hope this helps you in learning the many ways you can read chords on your guitar.