Strategy:Turtle

Turtle is a common reference for strategies involving hiding behind fortifications while focusing on building armies or economy, it is most commonly employed to counter the Rush.

Age of Empires III
It of debatable use in Age of Empires III, finding success with some (especially when mixed with Boom elements) while others swear off it completely in favor of other strategies (especially those giving early Map Control). Against AI opponents on lower difficulties it can prove very effective as well as entertaining.