Each year, Moltke selected the best twelve graduates from the "Kriegsakademie" for his personal training as General Staff officers. They attended theoretical studies, annual manoeuvres, "war rides" (a system of tactical exercises without troops in the field) under Moltke himself, and war games and map exercises known as "Kriegsspiele". Although these officers subsequently alternated between regimental and staff duties, they could be relied upon to think and act exactly as Moltke had taught them when they became the Chiefs of Staff of major formations. Moltke himself referred to them as the "nervous system" of the Prussian Army. In the victories which the Prussian Army was to gain against Austrian Empire and France, Moltke needed only to issue brief directives to the main formations, leaving the staffs at the subordinate headquarters to implement the details according to the doctrines and methods he had laid down, while the Supreme Commands of his opponents became bogged down in a mountain of paperwork and trivia as they tried to control the entire army from a single overworked headquarters.