Large chunky thick glass vase help please

Hi, i would appreciate any help in identification of this glass vase please. it weighs 2.1kg , the base is 6.5 inch square and it is 11 inches tall. there is a fish, or more likely a whale embossed into one face of the square bottom. There is fault line in the vase swirling around it from top down, however it has been suggested by a friend that this may be part of the design as a fishing line ending in the fishes / whales mouth. I cannot follow the line well enough to confirm this.

I don't know, but often Japanese glass from the 60s/70s has that sort of textured 'waxy' look, so I might start there.

Thanks for your reply/help chas. i will endeavour to dig further although so far i am hitting a brick wall.

Did you ever find out any additional information regarding this vase?