Venom Invented Black Metal

If you listen to Venom's "wellcome to Hell" (that's their first album) to me it sounds more "black" and dark than anything that ever preceded it but by the time they wrote and recorded "Black Metal" they had already begun to speed things up , possibly competing with bands like Motor Head who were more punk than metal musically . Almost all the early B.M bands from Norway have that punk vibe like wise early thrash bands from USA have something similar going on that relate back to Maiden , Priest , Venom , Motor Head ...

What the bands from Norway did was copy Bathory a Swedish band that began as a cross over between Venom and Motor Head but using a vocal copied from a japnese punk band called "Gism" visit https://www.youtube.com/watch?v=VI3NaLadm2Y.
Note that no parts of that cross over originates from Norway .

If we are talking about 90's Black Metal then you would have to say that Norway picked it up late, refined the formula and then made it popular .
IMO the first hint of black metal was the song "black sabbath" opening with the thunderstorm (this kind atmosphere dominated early Bathory) as the intro hence the ref "Black"
 
This is a bit confusing. On the one hand, you say that Norway didn't invent it because those bands were the second wave of BM, which is true. On the other hand, you also don't give credit to Venom, although they played a major part in the First Wave of Black Metal.

Because this First Wave consisted basically of bands like Venom, Bathory, Hellhammer/Celtic Frost, Sodom, Destruction and so on, whose music at that time was called Black Metal.

And I think that's exactly the important point here. Those First Wave-bands didn't play music you'd call Black Metal nowadays. This style was probably indeed developed in Norway in the early 90's (and called Death Meal in the beginning, e.g. by Euronymous, to set it apart from the 80's Black Metal). But the term and this type of poorly produced Heavy/Thrash with weird vocals and satanic vocals first called Black Metal originated in the 80's. Venom weren't the sole inventors, but they were one of the most important bands to shape it.

And since we're talking videos already, one of the best (and probably most entertaining) takes on documenting Black Metal's history was performed by one of Norway's most kvlt BM-vets, Darkthrone's Fenriz:

http://www.youtube.com/watch?v=y9-5urh814s

http://www.youtube.com/watch?v=YdyvXc_-M7U

edit: after reviewing Fenriz and thinking about it, I think the biggest credit should go to Quorthon. But Venom were pretty important as well.

The most profound influences are left out or down played , maybe out of ignorance but fairly accurate after about 1984 Japan's "G.I.S.M" was the source of the vocal style that inspired Bathory I cant regard it as witchy.... sorry.. lol it has hard core punk roots .
G.I.S.M 's "shoot to kill" Sounds a little bit like Darkthrone doesnt it ! ;)
Anyway this is all academic , the only reason Black metal raised its ugly head in the 90's is because no one could top reign in blood .