Supreme Headquarters Allied Powers Europe government offered Camp Casteau, a 2 km² Belgian Army summer training camp near Mons, which was an area in serious need of additional economic investment. In September 1966, NATO agreed that Belgium should host SHAPE at Casteau. SHAPE closed its facility at Rocquencourt near Paris on 30 March 1967, and the next day held a ceremony to mark the opening of the new headquarters at Casteau. The drawdown of the British Mediterranean Fleet, the military difficulties of the politically decided command structure, and the withdrawal of the French from the military command structure forced a rearrangement of the command arrangements
Supreme Commander for the Allied Powers only to prevent the imperial family being indicted, but also to slant the testimony of the defendants to ensure that no one implicated the Emperor. High officials in court circles and the Shōwa government collaborated with Allied GHQ in compiling lists of prospective war criminals, while the individuals arrested as "Class A" suspects and incarcerated in Sugamo Prison solemnly vowed to protect their sovereign against any possible taint of war responsibility. As Supreme Commander for the Allied Powers, MacArthur also decided not to prosecute Shiro Ishii and all members of the bacteriological research units in exchange for germ warfare data