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.
|------| time before
|---| time for N moves
|------| time after
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.
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.
- 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.
Where did the name come from? Why "Canadian" time? A chess thing?
Robert Pauli: No chess thing. See The Origins of Canadian Byo-Yomi.
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!
- Round Down Timing (generalization)
- Steady Average Timing (non-spilling variation)
- Total Average Timing (non-spilling variation)
- BGA Tournament Rules