Which Mega Man game introduced the Double Gear system?

Mega Man 11 is the Mega Man game that introduced the Double Gear system.

The Double Gear system gives Mega Man two temporary abilities: Speed Gear slows time, while Power Gear increases the strength of his attacks. The two systems can also be activated together in an emergency, although doing so places severe strain on Mega Man and leaves him weakened afterward.

The system is central to Mega Man 11’s story. A flashback reveals that Dr. Albert Wily developed the technology years earlier while studying at Robot University with Dr. Thomas Light. Wily believed enhanced speed and power would make robots more respected, while Light worried that pushing robots beyond their limits would have dangerous consequences. Their disagreement helped destroy their friendship.

In gameplay, Speed Gear is useful for avoiding fast attacks and navigating difficult sections. Power Gear makes charged shots and special weapons more powerful, but it consumes more resources and can cause the system to overheat. Mega Man 11 also returned several classic abilities, including the charge shot and slide, after their absence from Mega Man 9 and Mega Man 10. The Double Gear system remains the defining mechanic of the 2018 game.