Simultaneous flag-fall

The term does not require proof that both flags fell at the exact same instant. It describes the practical case in which both are down and the arbiter cannot determine which one fell first. An electronic time display may preserve enough information to establish the order; when the order is known, the ordinary rule applies to the first flag.

FIDE addresses this case in Guidelines III, which apply only when their use was announced for the event. They are intended for standard and rapid games without an increment, meaning longer or intermediate time controls, and not for blitz, the very short time-control format.

Effect by playing period

• If another playing period remains, the game continues.
• If this is the final period in which all remaining moves must be completed, the game is drawn.

Outside those guidelines, the tournament or platform regulations may prescribe a different procedure. This situation is not the same as a draw on time, where the first expired clock is known but the opponent cannot checkmate through any legal sequence.