“Zen master lessons increase hand infantry attack.”—In-game description
Master Lessons is a technology in Age of Empires III: The Asian Dynasties that can be researched at a Trading Post built on a Zen Temple settlement. Once researched, it increases the attack of melee infantry by 10%.
Master Lessons greatly depends on how much melee infantry the civilization possesses. For instance, the Aztecs can get much use of this, having four standard melee infantry units, while the Ottomans can only upgrade mercenaries and native warriors, having no standard melee infantry.