OK then, here goes. Won't bother with specific albums, too dunk and tired to exert the effort just go under the assumption that earlier=better. 
For the same reason this will likely be extremely lacking, will make addendum when i wake up and remember what im talking about

thrash

Casbah
Sacrifice
Shellshock
Jurassic Jade
Ground Zero
Doom
Deathblow
Rosenfeld
Raging Fury
Dementia
Xenolith Oger
Zadkiel
Riverge
Rommel
Aion


heavy/power/melodic/weird/misc

Crowley
Bellzlleb
White Hell
Sabbrabells
Girl Tique
Dante (1st demo only)
The Datura
Front Guerilla
United
Sniper
Prowler

death/grind/hardcore/etc

G.I.S.M. (obv)
S.O.B.
Multiplex
Guillotine Terror

Love the Japanese scene and obsessively collect it, there's always some western influence (Ground Zero is obviously Slayer worship, etc) but they 
always seem to add their own flair to it and make it something pretty unique.