The left hand is usually blamed for making sweep picking difficult. In reality, bringing it in at the wrong time — before the right hand is ready — is what causes the problem. Diagonals are the safest way to introduce the left hand to sweeping without getting tangled in theory or complex shapes.
What you’ll get out of this lesson: A left-hand introduction exercise using diagonal finger placements across four strings, practised in both normal and inverted positions, that develops even sweep timing without requiring any music theory knowledge.
What a diagonal shape is
A diagonal shape simply means placing each finger on a successive fret and a successive string, creating a staircase across the fretboard. The starting position: first finger on the 5th fret of the D string, second finger on the 6th fret of the G string, third finger on the 7th fret of the B string, fourth finger on the 8th fret of the high E string. Sweep up through that shape, then invert it — first finger moves to the high E string, second to B, third to G, fourth to D, keeping the same fret assignments — and sweep back down. Chain the two directions together and you have the basic exercise.
Building it up
Once the basic shape and its inverse are working, start shifting positions. Sweep up the diagonal, then move up a fret and sweep down the inverse. Move up another fret and sweep up again. Work the whole length of the fretboard, then come back down. Then take the same pattern onto different string sets: A, D, G, B instead of D, G, B, E. Then the lower four strings. After that, start combining string sets and positions randomly — change string group, change fret, change direction in no predictable order. The goal is to be able to maintain even timing and clean articulation no matter where on the neck you are.
Once you’ve got it up to speed, start doing it randomly at different points, making sure you’re hitting the outside strings — do that.
What to listen for
The main technical trap is losing the rhythm when you change direction. Each string should sound at an even interval — if the turnaround sounds like a stumble, slow down and smooth it out before increasing tempo. As a bonus exercise, try to identify what kind of chord or arpeggio each diagonal shape is outlining — they’re built in stacked fourths, which gives a modern, ambiguous sound and a useful ear-training exercise alongside the technique work.
Taking it further
Once you’re moving the diagonal around the neck fluidly, experiment with five-string diagonals, or with starting on the inverted shape rather than the standard one. You can also try introducing a slight rhythmic accent on the first note of each shape, which starts to make the exercise sound more musical and prepares the movement for use inside actual sweep arpeggios.
Your homework
Start slow — genuinely slow, where every note is even and controlled. Spend your first session just on the four-string diagonal and its inverse on one string set, getting the direction change smooth. In your second session, add a second string set. By the end of the week, aim to move between three different string sets in random order without losing the beat. Use a metronome throughout.