Each three-team alliance prepares in three ways:
- Build steam pressure. Robots collect fuel (balls) and score it in their boiler via high and low efficiency goals. Boilers turn fuel into steam pressure which is stored in the steam tank on their airship – but it takes more fuel in the low efficiency goal to build steam than the high efficiency goal.
- Start rotors. Robots deliver gears to pilots on their airship for installation. Once the gear train is complete, they turn the crank to start the rotor.
- Prepare for flight. Robots must latch on to their airship before launch (the end of the match) by ascending their ropes to signal that they’re ready for takeoff.
FIRST STRONGHOLD is played on a 27 ft. by 54 ft. field. Each alliance commands one tower, five defenses, and a ‘secret passage’ which allows their robots to restock on ammunition, called boulders. One defense in each alliance’s set of five, the low bar, is a permanent part of the field. Three defenses are selected strategically by the alliance prior to the start of their match. The final defense changes periodically by audience selection. Each FIRST STRONGHOLD match begins with a 15-second autonomous period in which robots operate independently of human control. During this period, robots attempt to cross opposing defenses and score in the opposing tower.