Calibre IWC 81 was the first automatic watch movement from IWC.

IWC had been working on an automatic watch movement since at least 1944, when Albert Pellaton of Le Locle became Technical Manager for the company. Their first design was granted a Swiss patent on June 14, 1946 but was the bumper automatic system and was never produced. On June 7, 1950, IWC applied for a second automatic movement patent. This featured a pawl-based system and would come to be known as the Pellaton winding design. This solution is particularly reliable and shock-resistant and, with two pawls “pulling” the barrel, extremely efficient as well.

Cal. 81, introduced in 1950, introduced this winding system to the public. It was a small seconds movement and was shortly joined by Cal. 85 with central seconds. Both were replaced in subsequent years by Cal. 852.