A double-stop is when you play two notes at the same time. Some people might say that’s a chord but a lot of guitar players only consider a chord to be more than two notes, so we call two notes a double-stop. The basic effect of playing double-stops is of harmonizing with your solo playing. This technique was used by many lead guitarists in bands of the fifties and sixties. Chuck Berry was a champion of double-stop playing.
One way of playing a double stop is to play two adjacent strings at the same time. Another way is to play two strings that are not next to each other by strumming with your plectrum and muting the string in the middle. Or you can put your pick between your teeth and pluck the two strings you want to play.
Here is a C major scale played up the fretboard on the first and second strings using double-stops:
e–0–1–3–5–7—8–10–12—————–|
B–1–3–5–6–8–10–12–13—————–|
G——————————————–|
D——————————————–|
A——————————————–|
E——————————————–|
And here is the same scale played in the open position across the fretboard:
e———————–0———————|
B————–0–1–3–1———————|
G——–0–2–0–2–4————————|
D–2–3–2–3———————————|
A–3–5—————————————|
E———————————————|
Here is a video showing you how to play double-stops:
