Smurfing

Smurfing is online slang rather than a uniformly defined chess rule. In chess it commonly describes an experienced player using a new or secondary account whose apparent rating, the number used to estimate competitive playing level, is far below the player's real strength, allowing them to face opponents who expect someone of that displayed level.

Creating a new account does not automatically make someone a smurf. New ratings need time to settle, and platforms permit additional accounts only under particular conditions. Chess.com, for example, requires approval for additional accounts and treats unauthorized speedruns, series in which a strong player tries to climb quickly from a low rating, as rating manipulation. Lichess also restricts multiple accounts while listing specific exceptions.

The term overlaps with sandbagging when a player deliberately loses to keep the secondary account low, but the concepts are not identical. Sandbagging focuses on intentionally lowering displayed strength; smurfing focuses on competing through an identity or account that hides a large strength difference. It is also not the same as account sharing, because a smurf can be one person using their own secondary account.