Hunting for 1st pressings

Easy to identify with Japanese pressings from 70s. I hunt for Japanese first pressings pro - very rare and quite expensive.
I never pay much for sealed records. Even if they are not re-sealed, you never know what's in there and the condition. Sometimes vinyl deteriorates substantially with age. When I say I don't pay much I mean over $100.

First pressings are often if not always best sounding and worth pursuing.

As an example. I have Pangaea by Miles Davis on Japanese vinyl, three pressings - original pro, original regular and same year reissue.
There is no doubt that the original regular is better sounding than reissue, and the pro is better still and not by little.
Another interesting example comparing original American and original Japanese. Bitches Brew by Miles Davis. They sound somewhat different - the American is a little more raw and edgy and Japanese is quieter and more refined, both are quite dynamic. I listen to both American and Japanese, though Japanese more often.
And the last example. Inner Mounting Flame by Mahavishnu Orchestra. Original Japanese and Japanese first reissue. They sound different, the original is a little more dynamic and the reissue is more refined and a bit laidback. Both great, I listen to the original.