Age of Empires Series Wiki

Grants Japanese Monks the Stealth ability in addition to a passive Dodge ability.
—In-game description

Intonjutsu Stealth is a technology in Age of Empires III: The Asian Dynasties that is unique to the Japanese and can be researched at the Monastery once the Commerce Age is reached. Once researched, it allows the Sohei Archer to use stealth mode and gives them the Dodge passive ability which allows them to occasionally evade incoming attacks.

Monastery technologies in Age of Empires III
Flag ChineseDE ChineseTraining Forms · The Five Precepts · Supreme Ultimate Fist · Slow Motion Routines
Flag IndianDE IndiansWhite Tiger Training · Improved Healing · Terror Charge · Crushing Force
Flag JapaneseDE JapaneseReiki · Intonjutsu Stealth · Kyudo · Kayakujutsu