Likely a TM or other brand from Japan.
ASGK is a "regulatory" marking that means it's built for Japanese market specs AFAIK only Japanese companies have those markings.
As for the gun itself. Looks like a springer but don't quote me on that, TM made a bunch of springers but they're kind of hard to find outside of Japan these days. However since it's half cocked and kind of in battery position I suspect it's probably a GBB pistol.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE