The rule
On clashXO, X always moves first. This keeps every match consistent and easy to verify on the server.
Creator mark choice
The creator can choose X or O. If the creator chooses X, they open the board. If the creator chooses O, the opponent opens as X.
Why this matters
Mark choice changes the first-turn advantage and the psychology of the match. Some players prefer taking initiative as X, while others prefer responding as O.
Fairness comes from consistency
Because the rule is fixed, both players know exactly how the turn order will work before the first move is made.