Slash Chords are a common form of chord notation, often used when notating guitar parts.
You've probably seen them if you've been reading online tablature. Let's look at how they work!
A slash chord is written as a chord name, followed by a slash, and then an additional note.
This is telling us to play the written chord, with the additional note after the slash acting as the bass note (the lowest note in the chord).
For example, a common slash chord is: G/B.
This means we need to play a G chord with B as our lowest note.
We can easily accomplish this with our open G shape, by omitting the note on the low E.
Since we've made our bass note B, and we still have all the notes of a G chord above it (G-B-D), we've fulfilled the requirements and found a valid G/B chord!
Most commonly, slash chords are simply a way of notating an inverted chord. Inversion is is a topic we will look into more as we advance.
This doesn't necessarily have to be the case, though! A slash chord can be any chord with any note as a bass note.