What phrase indicates it is time for the first rank to start the exercise?

The phrase that indicates it is time for the first rank to start the exercise is "Go." This term is commonly used in physical readiness training and military drills to signal an immediate action or initiation of an exercise. It provides a clear and direct cue for participants to commence their movements, ensuring that there is no ambiguity about when to begin. The use of "Go" establishes urgency and a synchronized start among all individuals involved.

Other phrases like "Begin," "Ready," and "Start" may imply preparation or readiness but may not convey the same level of immediacy and clarity as "Go." In a military context, precision and timing are crucial, and "Go" effectively communicates the precise moment to execute the action.