Fischer bonus time in Go
Fischer bonus time — often just called bonus time in Go — adds a fixed number of seconds to your clock after every move you complete. Unused bonus accumulates, so playing quickly builds a reserve you can spend later. A setting of 60 minutes + 20 seconds per move is the current American Go Association standard. An optional maximum-time cap stops the clock filling past a ceiling.
How the bonus works
The mechanism is simple, and it starts from move one rather than after main time:
- You begin with your main time — say 60 minutes.
- You make a move. The moment you press the clock, your bonus is added — say 20 seconds.
- If your move took less than 20 seconds, your clock is now higher than before the move. That difference is banked and stays banked.
- If your move took more than 20 seconds, your clock is lower than before, but by less than the time you actually spent.
- If your clock reaches zero, you lose. There is no overtime — the bonus is the mechanism that keeps you alive.
Play 30 moves in 5 seconds each with a 20-second bonus and you finish those 30 moves with more time than you started. This is the defining property of Fischer: it is the only common Go system where your clock can go up.
Why the AGA switched to it
The American Go Association runs its tournaments on bonus time. The US Open is played at 60 minutes + 20 seconds per move, and the AGA publishes rated-game minimums that give organisers a choice of pace:
| Setting | Character |
|---|---|
| 60 min + 20 s | US Open format — generous main time, comfortable bonus |
| 30 min + 10 s | Shortest of the rated minimums; brisk |
| 20 min + 15 s | Middle ground |
| 10 min + 20 s | Little main time, but a bonus large enough to keep playing indefinitely |
The practical argument for bonus time in a tournament is scheduling. A byo-yomi game can, in principle, run forever — every move resets the period, so two determined players can play three hundred moves at 29 seconds each. Bonus time has the same anti-flagging protection but the clock still trends downward under normal play, so rounds finish closer to their planned length. That predictability is what a tournament director needs.
The maximum-time cap
A cap is a ceiling the clock never fills past. With 10 minutes + 5 seconds and a cap of 10 minutes, a fast sequence of moves tops you back up towards 10 minutes but never beyond it.
Caps exist to stop a specific tactic: in a position with many forced moves, a player can grind out a large time reserve by playing the obvious answers instantly, then use that reserve elsewhere. Whether that is skill or exploitation is a matter of taste, which is why the cap is optional. It is common in online settings and rare in over-the-board tournaments.
In Byoyomi Timer the cap is a separate field on any Fischer control, and setting it to zero means no cap.
Fischer versus byo-yomi
| Fischer bonus time | Japanese byo-yomi | |
|---|---|---|
| When time is granted | After every move, from move one | Per move, only after main time ends |
| Can time accumulate? | Yes — this is the point | No, never |
| Guaranteed time per move | Only the bonus itself | The full period, every move |
| Rewards | Playing efficiently | Playing consistently |
| Risk | Clock can still hit zero | Only the final period can end the game |
The deeper difference is what happens when you are in trouble. In byo-yomi, a hard position late in the game still gives you the full period — the system does not care that you used your main time badly. In Fischer, a hard position late in the game gives you whatever you saved earlier plus the bonus. Fischer makes early time management matter for the whole game; byo-yomi resets the account.
Both are legitimate, and many players prefer whichever they learned first. See the full comparison for how they change the way a game feels.
The name
The system is named after Bobby Fischer, who patented a chess clock built around it in 1988 and argued that increment removes the ugliest part of time trouble — losing a won game because you could not physically move the pieces fast enough. Go adopted the same idea and generally calls it bonus time; OGS uses Fischer as a default for several game types.
Turn your iPhone into a real Go clock
Byoyomi Timer plays every Go time system — byo-yomi, Canadian overtime, Fischer bonus time, Ing — and reads the seconds aloud like a human timekeeper.
Coming soon to the App Store