Read the Time Control Before You Play
The clock is not merely a countdown display. It determines when a move is completed, how much time is added or delayed, when a checkpoint is reached, how lateness is treated and whether a flag fall changes the result.
Before round one, identify the exact control—not just a shorthand such as “90+30”—and read the event's default-time rule. A player who understands the base time but misunderstands the increment, delay or move counter can make a procedural mistake even while playing good chess.
The chessclock is part of competitive procedure, not merely a display of time. Players must know the actual control, the clock mode, the default time, when flag-fall is established and how defects/settings are handled.
Core rule Read the event's clock configuration before relying on assumptions about increment, delay, move counters or lateness.
Using the Chessclock
Chessclock
A chessclock has two linked time displays so only one can run at a time; flag-fall means expiration of allotted time.
Start White's Clock
At the scheduled start, White's clock is started under current Article 6.6.
Press Own Clock
After making a move, a player presses their own clock to pause it and start the opponent's clock; the interval before pressing remains part of the player's allotted time.
Improper Clock Handling
Improper handling includes pressing forcibly, picking up/knocking over the clock or pressing it before moving; penalties fall under Article 12.9.
Clock Placement
The arbiter decides clock placement before the game.
Move Counter
A move counter on a clock is useful equipment data but does not by itself settle claims; Article 6.12.2 forbids relying only on displayed information for a claim.
Time-Control Structure
Base Time
Base time is the principal allotted thinking time before per-move additions or later periods are considered.
Time Period
A time period is a part of the game in which a required number of moves or all remaining moves must be completed within specified time.
Move-Count Checkpoint
A move-count checkpoint such as 40 moves in 90 minutes is a time-control requirement; exact event controls must be announced in advance.
Sudden-Death / Final Period
A sudden-death/final period requires all remaining moves in the allotted final time; quickplay-finish provisions may apply only under announced conditions.
Increment
Increment/cumulative time adds a specified amount in association with each move according to the configured control.
Delay
In delay mode, a fixed extra interval runs before main thinking time begins to decrease; unused delay does not accumulate like cumulative increment.
Saved Time Carry-Over
Time saved in one period carries to the next where the control provides for it.
Read the Actual Clock Mode
Read the actual clock mode. Identical-looking +30 descriptions can mean different practical behavior if one system uses increment and another delay.
Lateness & Default Time
Default Time
Default time is the permitted lateness interval specified by the event regulations.
Event-Specified Default
If the event specifies a default time, that event-specific value governs subject to the Laws.
Zero Default if Unspecified — Current Law
Under current Article 6.7.1, if the event regulations do not specify a default time, the default is zero.
Neither Player Present
If neither player is initially present and the event has a non-zero default time, current Article 6.7.2 normally charges elapsed time to White unless the event regulations specify or the arbiter decides otherwise.
Arbiter Discretion Where Applicable
The Laws preserve arbiter discretion in defined lateness/default situations; do not rewrite that discretion as an automatic universal exception.
Flag Fall & Results
What Flag Fall Means
Flag-fall means the allotted time has expired; whether that produces loss depends on the relevant time-control requirement and mating-possibility exception.
Arbiter Observation
A flag is considered fallen when the arbiter observes it or either player makes a valid claim.
Player Claim
A player may claim flag-fall under the applicable Laws; in reduced-supervision rapid/blitz, specific appendix rules affect when/how flag-fall is acted upon.
Loss on Time
Normally a player who fails to complete the prescribed moves in time loses.
Cannot Possibly Mate Exception
The time-loss result is a draw if the opponent cannot checkmate the flagged player's king by any possible series of legal moves.
Both Flags
Both-flags situations depend on the applicable time period/appendix/guideline and what can be established; do not apply one blanket rule to every format.
Quickplay-Finish Cross-Reference
Quickplay finishes are covered by Guidelines III only when announced and within their stated standard/rapid no-increment scope.
Clock Problems & Arbiter Corrections
Clock Defect
An evidently defective clock is replaced by the arbiter, who uses best judgement to determine the replacement times.
Wrong Clock Setting
If a wrong clock setting is discovered, the clock is stopped and the arbiter installs the correct setting and adjusts times/move counter as necessary using best judgement.
Pausing Clock for Arbiter
A player may pause the clock to seek arbiter assistance for a valid reason; the arbiter determines whether the pause was justified.
Practice
Clock Practice
Clock practice can include controls with checkpoints, increment, delay, default-time scenarios, flag claims, defects and mating-possibility exceptions.