The Kwk 36 was an 88mm cannon used by the German Wehrmacht, during World War II. This was the primary weapon of the Pzkw VI Tiger I tank.
Although it is often said that this gun was based on the Flak 36 88mm anti-aircraft gun, in fact there was no similarity. The KwK 36 was built to practically the same design as the 75mm and 50mm guns already used in German tanks, but with the structure scaled up considerably. The breech ring was square in section and 320mm on a side.
See also: KwK 43 L71