Seven strokes a second, every one of them aimed at the floor. That is the arithmetic of metal downpicking at the tempo of "Master of Puppets", roughly 212 beats a minute in steady eighth notes, and the right hand that has to meet it cannot use the easy way back up. The right hand that built a career on refusing the upstroke, and sent a generation of teenagers back to the same riff until their forearms seized, belongs to James Hetfield of Metallica.
Defined as plainly as possible, downpicking means striking the string with the plectrum travelling towards the floor on every note, never on the way back. The return trip still has to happen. It simply carries nothing, the pick lifting clear of the string and going round again, so that a riff of eight notes costs the hand eight full cycles of travel where alternate picking, down and up and down and up, would have paid for the same eight notes with four.
A copperplate clerk with a pointed nib presses on every downstroke, so that the two tines spread and lay down a broad, dark shade, and lifts the pressure on every upstroke, leaving a hairline so thin it vanishes when the page is held at arm's length; the whole alphabet of that hand is built from the alternation, heavy down, weightless up. Alternate picking writes a riff in copperplate. Downpicking presses the nib on every stroke, all shade and no hairline, and tears the paper if the hand is careless.
That is the whole reason for the technique. It is not speed. At the same tempo alternate picking is easier, faster and kinder to the tendons, and every guitar teacher says so. What the downstroke buys is sameness: every note struck from the same side, at the same angle, with the same muscle, until the riff arrives as a row of identical blows and not as a pair of alternating ones.
Nobody arrives at it by talent. The method every teacher hands out is a ladder: a riff of steady eighths at a tempo the hand can hold for five minutes without tightening, the metronome raised a few beats at a time over weeks, and the whole exercise stopped the moment the forearm starts to burn, because a tendon pushed past that point does not come back stronger, it comes back inflamed. The fast ones are the patient ones.
What metal downpicking does to the note
The difference between the two strokes is small on paper and obvious on a record. On a chord the downstroke meets the thick low string first and the upstroke the thin top one, so the two strokes voice the chord from opposite ends; on a single low string the gap narrows, but the upstroke still tends to arrive a shade lighter and brighter, because the hand is pulling against its own weight rather than falling with it.
Played alternately, a stream of eighth notes carries that faint limp inside every pair, strong and weak, strong and weak, the rhythm of a march. Played all down, the limp is gone. Nothing in the bar is accented because everything is, and the ear, hearing no pattern of stress, reads the riff as a machine running at constant load rather than as a man playing it, which on any honest reading is what the players of the eighties were chasing.
A right hand borrowed from the Ramones
The source was not a metal band at all. The Queens quartet in leather jackets and torn jeans whose debut album went out on Sire in April 1976, fourteen songs in under half an hour and "Blitzkrieg Bop" first among them, was the Ramones, and the guitarist who played nearly every one of those barre chords with a downstroke, at a tempo that hacked the dead wood off every long rock song of the decade, was Johnny Ramone.
Johnny did not mute the strings the way the metal players later would. His downstrokes rang open, a wall of barre chords held on a Mosrite and sawed at from above, and the stamina it took to keep that up through a whole set became part of the band's legend. The heresy of a punk band had become a metal guitarist's curriculum.
The other half of the lineage was a rivalry in a Los Angeles rehearsal room. The guitarist Hetfield has described writing riffs against, each man trying to hand the other something he could not play, and each answering with a faster one, was Dave Mustaine, who stood beside him in Metallica from 1981 until he was dismissed in April 1983.
Mustaine took his side of the contest to Megadeth, whose debut Killing Is My Business... and Business Is Good! came out on Combat in June 1985, and the right hand of thrash was set by two men who had spent a year trying to break each other's wrists with riffs. The New York guitarist who carried the same stroke into Anthrax was Scott Ian. Thrash has its own account of what they did with it.
Heavy metal before them had mostly used the downstroke the way a painter uses black, for emphasis, on the heavy chords at the front of a phrase, with the running notes in between picked both ways. What the thrash players did was take the emphasis and make it the whole of the line, which is why a downpicked riff from 1983 sounds heavier than a faster alternate-picked one from 1980, and why the gallop players of the next decade, Jon Schaffer among them, held every stroke of their own figure to the same weight.
The arithmetic of seven strokes a second
Released in March 1986 as the title track of Metallica's third album, "Master of Puppets" runs past eight and a half minutes, and its main riff asks the right hand for eighth notes in an unbroken line, all down, for stretches that last longer than most punk songs, the wrist completing seven full cycles every second while the fretting hand does the moving. Filmed live and issued by the band as an official video, it shows the load being carried in real time.
Anyone who has worked a plunger churn knows the shape of that load. Every useful stroke drives the dasher down through the cream and every lift carries it back empty, and the arm tires on both, because the empty return weighs what the full stroke weighs; the butter only comes if the rhythm holds, and a churner who slows to spare the shoulder is still standing there an hour later. Downpicking pays the same double fare.
Alternate picking writes a riff in copperplate. Downpicking presses the nib on every stroke.
The body answers by moving the work up the arm. Players who last at it drive the stroke from the forearm and the elbow as much as from the wrist, keep the grip loose between strokes and let the pick escape the string on a slight upward slant after each downstroke, so the return trip clears the strings instead of snagging them. The calluses come where the pick presses the thumb, not on the fingertips.
Where the downstroke gives out
Every hand has a ceiling. Around the tempo of "Master of Puppets" sustained eighth notes begin to cost more than most players can pay over a whole set, and sixteenth notes at anything like that speed are beyond downpicking altogether, which is why the tremolo passages of the faster genres are played alternately and why even the committed downpickers switch strokes when a riff doubles its rate. The rule is a choice, not a religion.
What the technique cannot do is hide. A downpicked riff played slightly behind the click sounds tired rather than heavy, and a hand that sneaks in an upstroke to catch up is audible to anyone who knows the song. The chord under the plectrum, the tritone and the slackened string belong to that part of the story, the account of how the music is built note by note.
What a riff played this way does once it is placed inside a song, verse riff against chorus riff, the solo riff held back for later, is a matter of heavy metal song structure. The right hand only supplies the riffs. It supplies every one of them at the same weight.
