Technical thrash, from the outside in. Each step is a genre and the single record this encyclopedia would put on first. Play them in this order and the last one should sound like a next step rather than a wall.
- 1 The way in
Heavy metal 1970
It split off from hard rock and blues rock when Black Sabbath tuned down and wrote riffs on the tritone. Volume, riff and a code of its own - every branch below starts here.
Sung. Melodic singing throughout.
Put on
Black Sabbath - the song Black Sabbath. The first thirty seconds are the genre's birth certificate.
Black Sabbath, Black Sabbath (1970) - 2 Then
Thrash metal 1983
NWOBHM plus hardcore punk: palm-muted riffs, brutal tempos and lyrics about war and society. The first truly extreme branch.
Shouted. Barked or chanted, and you can still make out the words.
Put on
Slayer - Reign in Blood. Twenty-nine minutes that redefined the word extreme.
Slayer, Reign in Blood (1986) - 3 What you asked about
Technical thrash 1988
Thrash with dissonant chords, odd meters and bass up front. The bridge between thrash and progressive metal.
Shouted. Barked or chanted, and you can still make out the words.
Put on
Voivod - Nothingface. It includes a Pink Floyd cover that makes perfect sense.
Voivod, Nothingface (1989) - 4 Where to go next
Crossover thrash 1984
The exact point where hardcore and thrash metal merge: metal riffs, skate-park attitude, mandatory circle pit.
Shouted. Barked or chanted, and you can still make out the words.
Put on
Suicidal Tendencies - Institutionalized. The best song ever written about parents not listening.
Suicidal Tendencies, Suicidal Tendencies (1983)
Assembled from the tree: every genre Technical thrash descends from, in order. Technical thrash has no subgenres, so the last step is the genre that rates closest to it by sound.