Hi
I have done a lot of work with this material and I use a tile saw they are made to fit hacksaw blade holders and brought from any hardware shop. You can break them and tape to a tube as a holder ( holding them gives you blisters)and saw in normal way. Hope this is of help to you.
Jerry
Caution is a most valuable asset in fish keeping, especially if you are the fish.
My tip is also tortoise and the hare slowly slowly not to rush.Also pic of old tank of 10 years ago note the flower pot and saucer in middle all cut with one of them.
For a rough split, I tried something that worked out. I treated the pot as if it was a rock. Take a hammer and tap lightly along the line where you want it so split. Just go over the same line with that hammer a few times and eventually the locallized stresses youare putting into the pot will cause it to split along the line. Took me about 3 minutes once I got up the nerve to give it a try. Before that I had ruined a few cutting tools and damaged other pots badly enough that I was almost ready to give up.
Apparently, you can cut wet [as in soaked over night or so] terracotta with a regular hack-saw blade. I would probably just fire up my tile-cutter, but if you don't have one, it's a pretty expensive method to get a few pots cut - cheaper to buy a tile-blade for hacksaw, or just crack a few pots. I've been getting pre-broken pots (free!) from the local garden centres - they sometimes have a lot of various shapes of pottery.