I am not yet so lost in lexicography, as to forget that words are the daughters of earth, and that things are the sons of heaven.Samuel Johnson, Preface to A Dictionary of the English Language
Heavy metal albums wrote the definition of the genre long before any critic tried, one clause at a time, and most of the clauses were drafted by records that never topped a list. A definition is not a ranking. The best record of a given year and the record that fixed a rule for everyone after it are often two different sleeves in two different racks.
The Ordnance Survey's levellers once walked the whole country with a cold chisel and a mallet, cutting a broad arrow with a bar across its tip into the stone of church towers, bridge parapets and milestones, and every height on every map in the land was measured up or down from those cuts. Certain records were cut into the genre the same way. Every later band is measured from them, whether it has noticed the marks or not.
The four working men from Aston whose second album heads every ranking of the best heavy metal albums of all time also cut the first mark, and it was Black Sabbath: a riff that carries the song on its own back, with nothing propping it up from underneath. Paranoid needs no further ink. The other clauses were cut by other hands, some famous and some barely known outside the faithful.
The definition in heavy metal albums, clause by clause
- A riff carries the song on its own back.
- Two lead guitars, and a voice above them.
- The machinery may change. The march may not.
- Speed is permitted, and the singer still sings.
- The concert hall may be raided without apology.
- The rules outlive the men who wrote them.
- The definition still sells.
Two guitars and a siren: Judas Priest

The Birmingham five that went into the studio early in 1977 with Roger Glover of Deep Purple producing and a young session drummer named Simon Phillips behind the kit, and came out with the first record built around two lead guitars and a siren of a voice, was Judas Priest, and the album, its first for CBS, was Sin After Sin.
"Sinner" sets K.K. Downing and Glenn Tipton against one another like two lathes turning the same steel bar from opposite ends, shavings flying off both chucks, and Rob Halford climbs over them into a register no blues singer had ever needed. Even the cover of Joan Baez's "Diamonds and Rust" comes out in harness. Stained Class perfected the formula a year later. This record wrote it down first.
Two years on, the young British bands of 1979 took that template into the pubs wholesale, two guitars harmonising in thirds over a bass line that never stopped moving and a singer pitched somewhere above the smoke, and hardly one of them admitted where the drawings had come from. The clause was already signed. They only witnessed it.
New machinery, the same march: Iron Maiden
The band that carried guitar synthesisers into the studio in 1986 without giving up a single bar of its gallop was Iron Maiden, and Somewhere in Time, recorded at Compass Point in Nassau and finished at Wisseloord in Hilversum with Martin Birch producing again, was released in September 1986 and sent out Adrian Smith's "Wasted Years" as its single, the first the guitarist had written alone. The synthesisers glitter. The riff underneath them is the riff of 1982.
"Caught Somewhere in Time" opens the record at full gallop and "Alexander the Great" closes it at well over eight minutes, and the purists who swore the new sound was a betrayal were humming both within a month. The paint was new. The chassis was not.
The clause mattered more than the record. Once the band that had written the rules of the gallop had bolted new technology onto it and lost nobody, every later heavy metal band knew that keyboards, synthesisers and studio tricks could be added without a trial for heresy, and when Helloween put keyboards on Keeper of the Seven Keys a year later, nobody called a trial.
The purists who swore the new sound was a betrayal were humming both within a month.
Speed and the concert hall
The Toronto four that put a title track about the clang of metal on metal into the shops more than a year before most of the American thrash bands had a debut out was Anvil, Steve "Lips" Kudlow, Robb Reiner, Dave Allison and Ian Dickson, on the Attic label on 15 April 1982. On Metal on Metal, Robb Reiner's drums run at a pace critics have since called a direct template for the tempo thrash would claim as its own. The title riff works down the song like a bricklayer running a course down a factory wall, every block set at the same interval, no gap left for the mortar to show. Kudlow still sings over it. That was the clause: speed, and a singer. The band never sold like the thrash bands that followed it, and Metallica's Lars Ulrich has called Anvil the godfathers of thrash outright.
The Florida band that took Grieg's "In the Hall of the Mountain King" and turned it into a heavy metal overture was Savatage. Released by Atlantic in 1987 with Paul O'Neill producing his first record for the band, Hall of the Mountain King sets Jon Oliva's voice, half croon and half howl, against his brother Criss's guitar, and the orchestral borrowing is played at full volume with no apology in the liner notes. The overture, an arrangement of Grieg's theme, is called "Prelude to Madness", and it runs straight into the title track next on the record without a pause for breath. O'Neill would later build a whole orchestra out of the same idea. The clause had already been cut.
After the founders: the rules on their own
By the middle of the nineties the majors had cleared their racks of the style, and the next clause was written by people who had not been there the first time. The Swedish band founded by Oscar Dronjak, a guitarist who had spent the years before in the death metal band Ceremonial Oath, was HammerFall, and Glory to the Brave, released by Nuclear Blast on 27 June 1997, played twin leads, anthems and a clean high voice with the zeal of converts. It entered the German chart at number 38 in its first week, a position no debut heavy metal album had reached before it. The record even closes the circle by covering Warlord's "Child of the Damned". Critics laughed. German record buyers did not.
The proof that the definition had become a creed rather than a memory sits in that record. Nobody on it had cut a single in 1980, and every rule of 1980 was obeyed to the letter, recited the way a convert recites a catechism learned off the printed page, word perfect and louder than anyone born into the parish.
The last clause belongs to the Linköping band that hid its members behind masks and a skeletal papal costume and still went on to win a Grammy, Ghost. Opus Eponymous, released by Rise Above on 18 October 2010, sets "Ritual" and "Elizabeth" on clean riffs, organ and a sweet high voice singing hymns to the other side. "Cirice", from a later record, would win the band the Grammy for Best Metal Performance in February 2016. Reviewers reached for the same shelf of names to place the debut: the first two Mercyful Fate albums, and the occult rock of Witchfinder General a decade before them. It sold. The definition still does.
What the seven clauses keep out
A definition works by what it refuses as much as by what it admits, and the seven records above share their refusals as firmly as their rules. Not one of them uses a growl or a blast beat, not one tunes its guitars down to the depths death metal would later need, not one lets a rapper near the microphone or a sampler near the drums, and not one runs a riff for a minute without a melody riding somewhere on top of it. Those roads led to other genres. Heavy metal in the narrow sense is what remains when all of them have gone.
A definition written in albums leaves one quarrel open, which single song holds the whole of it in five minutes, and that argument belongs to the best heavy metal song. Each of the seven clauses has its own candidate. None of them agree.
The order in which these records arrived, and the bands and scenes around them, is told in the long version. Seven clauses, seven records, fifty years. Anyone can add an album. Nobody has yet struck a clause out.