Henry Halleck's General Hat

Origin
Henry Halleck was a Civil War general in the Western Theater who became general-in-chief to all Union armies and chief of staff to General Ulysses S. Grant. Halleck was cautious and believed in defensive maneuvers over quick attacks. He was a master of the political side of the war but held little control over battlefield operations; he was known by many as “Old Brains”.

Effects
When worn, the hat allows the user to retain military tactics and knowledge into the user's brain but removes memories deemed non-important to war, filling in the gaps with military knowledge.