It's a tough one. You can remove the sink baskets to give yourself a better handle.
And a nice sharp blade to cut the caulking.
The sheer weight of a 14" deep Cast Iron Sink -- top mounted onto a countertop.
I know it was just set it with caulk.
Just short of having PATIENCE as the tool of choice in my toolbox, is it just slowly working a putty knife in there to break the seal. She's one heavy mutha...firmly sitting on the countertop with a 1/32nd reveal showing that a knife score ain't going to break this bond.
An tricks of the trade I'm missing.
What is the countertop made of? That is the main question and determines your course of action.
Licensed residential and commercial plumber