Canadian Timing

Definition

Canadian Timing is the time system where

• one gets an amount of time (e.g. five minutes),
• time used for each move is deducted,
• and after each N-th move (e.g. 25th) the time used for the last N moves is added back.

Diagram

|------|  time before

|---|     time for N moves

|------|  time after

Remarks

Canadian typically is used after Absolute Timing to manage overtime. This is popular in amateur tournaments:

• Nobody has to waste his pause with counting seconds.
• No fancy clock is needed.

On Go servers it is common to have a very short main time (1 minute, say) followed by relatively short (overtime) periods (of 5 minutes, say), each taking 25 stones. "Anyone for a 1/5 game?" This leads to a game with a brisk and steady pace (or a manic pace, depending on your point of view). A 200-move game played as 1/5 will never last more than 42 minutes.

With only a plain clock, Canadian has to be emulated -- see below.

Emulation

The player gets

• a certain amount of time
• and a certain number of stones.

The player must play all these stones before that time runs out. An example would be 25 stones within 5 minutes, an average of one stone every 12 seconds.

If the flag falls, the player loses on time.

If the player gets rid of his stones in time, a new period starts and there is another set of stones to play:

• the player stops both clocks,
• the opponent resets the player's clock,
• the player counts out his next set of stones,
• they check,
• and the player starts his opponent's clock.

Note that

• After successfully playing the requisite number of stones within the given period, any time remaining in it is forfeited or spilled.
• A fallen flag is a loss, even if the "last" stone already hit the board!
• Players should close their supply to avoid using additional stones.
• Players should not forget to drop one stone back to their supply when they pass.

Questions

Where did the name come from? Why "Canadian" time? A chess thing?

Robert Pauli: No chess thing. See The Origins of Canadian Byo-Yomi.

Example

3 moves ("stones") in 3 minutes.

  #    Time   Stones    Used
  --------------------------
  1     3:00    3       0:40
  2     2:20    2       1:50
  3     0:30    1       0:29
  4     3:00    3       1:10
  5     1:50    2       1:45
  6     0:05    1       0:03
  7     3:00    3       2:10
  8     0:50    2       0:50
  9     0:00    1       lost

The two unused seconds in step 6 are spilled, and at most one more could have been used!

See also

• Round Down Timing (generalization)
• Steady Average Timing (non-spilling variation)
• Total Average Timing (non-spilling variation)
• BGA Tournament Rules