Shell Game was a Manticoran counter-intelligence operation designed to protect the secrecy of Project Gram, a military development program in the second half of the 19th Century PD.
It provided plausible origins for the weapons and technologies developed under Gram, using large parts of the Bureau of Weapons' regular research and development staff as a distraction for Havenite spies. Further protection was provided by the establishment of an 'official' BuWeaps black research project on Weyland, which functioned as a false target should anyone manage to figure out that the RMN had a secret research and development project. (Companion)