Renogaza from the looks of it the Japanese used a similar system as the US.
(Going from memory here, might be a little rusty)
The fulcrum point was just before the cutouts in the turret face.
The breech mechanism was probably an interrupted screw system
here's a picture of a US 16 inch gun turret, should be relatively close to the system the japanese used.
now, as for aiming.
on a good day the turret recieved information from the director on the foretop. This used radar to get precise range information and had a stereoscopic system as backup.
If the turret stopped receiving information from the fire control computer the turret would switch to local control. This was entirely stereoscopic, and thats why there are "wings" on the back part of the turret, this houses the lenses for the rangefinder withing the turret.
I had the good fortune to be inside the turret of a battleship at the last SUBSIM meet. I believe there are some pictures we got of the interior.