After production of the PT-76 was discontinued, Soviet engineers began work on developing a suitable replacement around a set of requirements provided by the military. The requirements were sent to three different design bureaus, with each bureau developing its own vehicle around the given specifications.

One of the proposed designs, the Object 788, was disqualified early from the competition due to being incomplete and missing several key features mandated by the requirements. The other two designs, the Object 685 and Object 934 were both deemed as sufficient, and work on them continued. By the mid 1970s, both vehicles were built and tested, but neither managed to garner enough interest to warrant a production order being issued. Despite not making it past the prototype stage, design solutions from both vehicles were later applied to other Soviet fighting vehicles.