The G6 Guitar Chord is found in the G Major Scale: G A B C D E F# G. It is made up of the 1, 3, 5 and 6 of this scale. Meaning the notes G, B, D and E.
G6 Chord notes: G B D and E
If you refer to the chord chart diagram below, you will see how to finger this chord. You will notice that the fingering is very much like the G Major chord only you are removing your fourth finger from the G note on the bottom E string.
Here is a key that will help you read the chart:
Everything on the above chart should be self explanatory, except for the last three in the third column. They may need a bit of explaining. The O, or open symbol, simply means that you do not press down on any notes on that string. The X means you do not strum that particular string. The Barre symbol means you need to barre that particular fret. When you barre a fret you are pressing down on multiple strings at the same time with one finger.
Chord Playing Tip
Be sure that you are pressing down on the strings hard enough and play each string one at a time to make sure you have a nice clean sound. If any of the strings buzz or sound muted, then something is not right.