In this video
The song I'm looking at is "Not 19 Forever" by The Courteeners, played with an A major triad. This is a huge lead guitar concept that is often overlooked and people don't see the benefit of it. This is why I've chosen this song. We're also needing to get the right hand moving a little bit quicker if we're going to be doing the lead lines coming up.
What is a Triad?
All a triad is, is the three notes that make up any major or minor chord. That same A major chord consists of the notes A, C-sharp, and E. When we play all five strings of an A major chord, we've got two A's, two E's, and then one C-sharp. So even though we're playing five strings, we're only playing three different note names. It's those same three note names we have when playing the thinnest three strings, which we call a triad. When we play a bar chord it's more thought of as rhythm guitar, but as soon as we're playing the thinnest three strings only, this is far more common for lead lines and lead riffs.
The Technique
We add two notes, one with the third finger, one with the little finger, so we can keep these first two fingers still and press these two fingers down to create the riff. Holding down two strings with this first finger is a really important thing to get used to for a whole world of lead guitar stuff. It's the same technique used in Chuck Berry riffs. This first finger holding two or perhaps later three strings is crucial for lead guitar playing.
Finger Positioning
That first finger needs to be down at the fifth fret on the thinnest two strings. We're going to have the thumb again just sitting on top, and we wrap that first finger around the back of the neck. We're comfortable in this part of your finger here - that's where we put that first finger for lead guitar stuff. Middle finger down at third string fret six, and we play that for a whole bar with eighth strumming. The lower part of my thumb is here muting the thicker three strings, but really I'm just trying not to strum from string four upwards.
The Pattern
After a bar, we put the third finger down at fret seven, then we can lift off the middle finger. Then the third finger goes down at the seventh fret on string two, and it's going to go between there and lift off. It's eight strums of the first position, eight strums of the second, then it's three with your little finger down, five off. That's repeated for the entire song. When that first finger gets quite tired, you can totally switch from having the thumb over the top to having the thumb down, and we can even use a capo at fret five. Key points: a triad are the three notes that make up any major or minor chord, and we're improving our right hand technique by playing faster strumming.

