The AZ hive originates from Slovenia and was created by Anton Žnideršič.
This style of hive is best described to be more like a kitchen cabinet with multiple chambers inside.The typical Slovenian design has 2 chambers each a little deeper than a Langstroth deep frame.
The beekeeper works the bees from the backside of the cabinet thru doors and the bees come and go thru the front side of the cabinet.
When you open an outer door you expose some inner doors that keep the bees contained behind screens.
Removing an inner door gives you access to the frames that sit on 3 rods evenly spaced.
Removing the frames is much like pulling a book off the book shelf as you just slide it towards you out of the cabinet.
The frames have coves on the top and bottom bars as to limit surface area to be propolized by the bees.
The one of many advantages to the AZ hive is you can access any level of the hive without any heavy lifting.
Here are a few pictures of my Hybrid AZ hives.
You can see more about AZ hives on these websites.