The prototype was initially presented on Photokina October 1966 as Pentax 220. It was not an actual sample but dummy. Some magazines presented the new camera in november 1966. By official catalog data the camera should be 6X7 format and able to make 10 shots on 120 film and 20 shots on 220 film. The name of the camera features support for recently released 220 films. The camera also should have: interchangable viewfinders, self returning mirror with lock up feature, electronic focal plane shutter powered by 6V Eveready 544 battery supporting speeds from 1 to 1/1000 sec and B. Some sources reported about standard 105mm f/2.4 lens that it was named “Hi-Takumar”. The date of production was not known. It was only introduction of technical data. There is no any sample camera was made. It is very difficult to discover original images of this Asahi advertising brochure. The camera should be with chrome finishing of top and bottom plates.
And finally, all these features introduced in the prototype were made only in Pentax 6X7 (MU) in 1976.
The images bellow were got from Asahi advertising catalog which was made just before Pentax 6X7 has been gone into production. This is extremely rare images of the camera with chrome finish. Unfortunately there is no actual camera images in the Internet. This sample shows slightly different battery lock adapted to use coin for open/close.
P.S. Special thanks to Rudi Hillebrand for contributing these images.