Has any nation's tank doctrine ever used ramming as a primary or secondary means of combat? I'm aware that Soviet tanks at the Battle of Kursk would ram German tanks once they (the Soviets) ran out of ammunition, but this seems to be an emergency measure rather than a deliberate part of doctrine. Is there any nation for which tank-on-tank ramming has been considered a primary or secondary tactic in the field?
In the Tiger Fibel (which is the Tiger tank's manual) it was explicitly stated that you should close in on targets and roll over them instead of using up ammo. While the images are in German, it can be found at: http://www.d13pfad.de/tigerfibel-english/
The page in question is page 91, which is basically dedicated to tell the tankers to not waste ammo or fuel.
It says: Nützt den dicken Panzer aus! Ran! (Use the thick armor, close in) Walzen ist billiger als MG! (Rolling over is cheaper than MG)
This could be interpreted as ramming as well, but it's not as explicitly stated as I had it in memory before rechecking the source.