The OP may be thinking of chopping up a salmon into salmon steaks. I see that all the time at the asian supermarkets. So yeah, that means chopping through the spine. You'll want something like the CCK BBQ chopper (or whatever it's called) or even a regular western cleaver for this. Likewise for chopping up chicken through the bones.
There are fancier alternatives, but a no-frills chopping cleaver will do the trick.
If you go to the Chinese website Chefs Mall, you will find they list what you are looking for under just the term "cleaver." As in an all purpose kitchen chopper to include chicken and fish bones. One bit of information I picked up in China on my last trip is that you use the heel of the blade for bone chopping and the front area for slicing on these. I have a Shibazi that is even marked in Chinese with arrows pointing front and back with that information.
I need to chop through drumsticks and thigh bones for various preparations, not just jointing. Thank you noodle soup that website has everything I'm looking for. KKF to the rescue.