Blitz chess rules: illegal moves, flag falls and disputes

The format is defined by time. Under the FIDE classification the boundary runs by the total time available to a player for the whole game, counting the increment over an assumed sixty moves:

• Blitz. Up to ten minutes per player for the whole game.
• Rapid. More than ten minutes and up to sixty.
• Classical. More than sixty minutes.

The common amateur controls - 3+2, 5+0, 5+3 - all sit inside blitz. Anything faster than three minutes is usually called bullet, which is not a separate official category but is treated as blitz for rules purposes.

Why the classification matters in practice: it determines which rating the games count towards, and it determines which set of rules applies - rapid rules.

The single biggest difference from classical chess, and the source of most disputes. In blitz an illegal move is punished far more severely.

What counts as an illegal move:

• Leaving your king in check or moving into check.
• Moving a piece in a way it cannot move.
• Castling when it is not permitted - through check, or having already moved the king.
• Capturing the king. Which is itself an illegal move, not a win, though many amateurs believe otherwise.

In a club event this rule is often softened: the arbiter simply restores the position and adds time to the opponent. That is a legitimate choice, but it has to be in the regulations - not decided on the spot when it happens.

In blitz the clock decides more games than the board does, so the details matter.

• A flag fall must be claimed. It is not automatic: if neither player notices and both play on, the game continues.
• Only a player may claim it - not a spectator, and normally not the arbiter unless the regulations say otherwise.
• If the opponent cannot mate by any series of legal moves, it is a draw. Running out of time with a lone king against a lone king does not lose - see insufficient material.
• The claim must come before your own flag falls. If both flags are down and nobody claimed in time, the game is drawn.

Practical note for organizers: digital clocks with an increment remove a large share of flag disputes, because the time never runs to zero unnoticed while moves are being made - about clocks.

• Notation is not required in blitz. Nobody writes moves down, and no claim can rest on a scoresheet.
• Which weakens repetition and fifty-move claims. Without a record they are almost impossible to verify, so in practice they are rarely upheld.
• The arbiter usually does not intervene on their own. In blitz the arbiter reacts to claims rather than policing the boards, unless the regulations state otherwise.
• One hand, always. Move with one hand and press with the same hand. This is the most frequently broken rule in blitz and the most frequently forgiven.

One organizational rule removes most of these: an arbiter within reach of the boards that matter. In blitz a dispute cannot be reconstructed after the fact - there is no record.

Five lines that settle nearly every argument before it starts - and they take a minute to write:

1. 1The exact time control, including the increment: «5+3», not «five minutes»
2. 2What happens after an illegal move: an immediate win for the opponent, or a restored position with added time
3. 3Whether the arbiter may call a flag fall, or only the players
4. 4How places are decided if players finish level - the tie-break order
5. 5Whether the event is rated, and by which body

And announce the first two out loud before round one: half the players will not have read anything - what to announce before the start, running a blitz evening.