Keywords: Equipment, Software

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Clocks are used to monitor and control the time each player has for his remaining moves. They exsist in many variations here an overview of the most common types.

Table of contents

Analog clocks

Analog Clocks used to be common mechanical clocks for face-to-face over-the-board games and tournaments. They have been surpassed in use by digital clocks.

A robust & famous version is the Garde clock.

Hardware-based digital clocks

[ext] LEAP

LEAP offers a few models that have most standard timings as well as byo-yomi and Canadian timing.


A moderately priced clock that has most standard timings (Fischer, byo-yomi, Canadian byo-yomi, etc.). It has a flaw in byo-yomi where if a player does not notice that the opponents time has run out and presses the button, it gives the opponent who should have lost on time another byo-yomi period. It is fairly easy to set up the desired timings. For regular byo-yomi, the remaining byo-yomi periods are displayed on the clock while playing. For Canadian byo-yomi a button must be pushed to manually recharge the time. The audible beep goes off on 10,5,4,3,2,1,0 sec. remaining in main time and each byo-yomi period. The sound is about perfect, not too loud or ear piercing of a tone.

  • LEAP PQ9912
Generally favorable reviews for quality. It does not display byo-yomi periods remaining.

[ext] Chronos

Chronos clock
Chronos clock

Chronos offers four clocks: two standard models, one with push buttons and the other with touch pads; and two blitz models, one with push buttons and the other with touch pads.
Has all kinds of byoyomi, overtime, Fischer, Bronstein, hourglass etc.. Very robust metal case. Intricate to operate.
See the Chronos Manual, as well as the discussion below.

[ext] ZMartfun (ZMF)

ZMF clock
ZMF clock

ZMF clocks are similar to Chronos clocks, but some models use LED instead of LCD. They suffers from the same non-intuitive setup as Chronos clocks.

[ext] DGT

DGT has several digital clocks on the market with an emphasis on ergonomy. Options vary.


Meant to be a new and improved version of the DGT2010 that was released in 2023. Has a [ext] reasonable byo-yomi implementation.


A relatively inexpensive byo-yomi clock.

  • DGT Easy
Released in 2006. Very simple to handle. The basic "Easy" model has only absolute time.
  • DGT Easy plus
The "Easy plus" model has a "delay" mode, a "bonus" mode and a buzzer. "Delay" is Bronstein Timing. "Bonus" is Fischer Timing.
  • DGT 2010 (replaced the DGT 2000 in October 2007)
The 2010 model by DGT. Main features for Go are Japanese byo-yomi. (With a maximum of 9 periods) and Canadian byo-yomi preprogrammed. Times can be set manually. The manual for the DGT 2010 implies that is has the same limitations on Canadian byo-yomi as the DGT XL: the time must be manually reset by pressing a button when the correct number of moves have been made.
Also useful the buzzer function of the DGT 2000 plus has been added in the 2010.
Advantages compared to the 2000 are the larger display, a better user interface ("-1" and "+1" button for inputting time) the new, silent lever mechanism and the buzzer.
  • DGT2010 Second Generation (replaced the DGT2010 in November 2010)

Dgt 2010 2nd Generation
DGT2010 2nd Generation

This is an update version which can be distinguished from the previous DGT2010 by the blue color of the buttons. Various improvement including automatic move counter added to Canadian Byo Yomi for Go.
[ext] This video shows an example of byo-yomi setup and sounds. Byo-yomi is displayed as total time. For example, five 30 sec. periods would be displayed as 2:30 when in byo-yomi. There are no warnings when a period is used or about to be used, except for the last period.

  • DGT XL(discontinued)
On the market since 2003. In a reversal from the 2000, the XL has Canadian byo-yomi, and not the Japanese. Since the Japanese method can't be easily simulated using one of the other time controls, this is a major disadvantage of this model.
Main advantages compared to the 2000 are a better user interface ("-1" button in addition the the "+1" for inputting time), and a buzzer.
  • DGT 2000 (discontinued, replaced by the DGT 2010 october 2007)
The older model. Main feature is that it has Japanese byo-yomi. (With a maximum of 9 periods)
Canadian byo-yomi can also be used, but only by manually adding extra time, like you do when you use analog chess clocks. This means you also must count the stones yourself during byo-yomi.
(Hint: The best timing method for this is probably the 3rd one. It does mean that, for each extra period, you have the specify the amount of extra time manually, but all the other time controls I tested do weird extra stuff that make them completely useless for this purpose. On the upside, you can see very easily when time has run out, at which point you can add extra time and start a new period.)


Excalibur Clock
Excalibur Clock

Good value. Can do Japanese and Canadian overtime.
Used along with Ing Clocks at the 2007 US Go Congress.


MeijinSen DIT-40
MeijinSen? DIT-40

Made by [ext] Citizen. Available through Kuroki Goishi Ten.
  • DIT-40 (Japanese, Chinese, English, Korean) with English buttons.
  • DIT-50 (Japanese and English) with Japanese buttons.

Ing Timer

Ing Timer's are not easily available to purchase on the open market. However they are a well known type of clock.

Software-based digital clocks for mobile devices

[ext] Chess Clock

Free and paid version Android app available on Google Play.
Supports sudden death, japanese byo-yomi, canadian overtime, Fischer, hourglass, Bronstein and additional time. Currently one of the best for Android. (2021)


Go clock for the Nintendo DS.

Go Clock for Android

Go Clock is a free clock app for Android.
[ext] (Android Market)
[ext] (SlideME)

[ext] ChessGoClock

Java app for phones it allows both japanese and canadian overtime. Written in J2ME.

Ginsei Igo

for Nintendo DS

Online clocks

[ext] timesqueezer one

Browser game clock, no installation is required! [ext] 'timesqueezer one' presets/setup;
Runs within the browser. Works on computers with keyboard as well as on touchscreen devices.
Settings can be saved within a browser bookmark.
Works offline, if you save( save complete with associated files ) the clock page 'ts1.htm' and the setup page 'index_133.htm' to the same directory.
JavaScript is required.

[ext] Pendule

Pendule is a simple browser game clock in javascript:
Works almost on any device. No installation is required.

Go server clocks

Which Go server supports which time system? These are explained and discussed at Go Servers and Time Systems.



One of the best clocks for playing Go face-to-face is the Chronos.

Chronos vs. DGT

A friend wants to buy a go clock. He's considering Excalibur II. A recent r.g.g. post mentions Chronos and DGT. Any suggestions? The comparisons on the net focus on chess... -- RafaelCaetano

Chronos hands down, without a doubt. My 1st chronos lasted for 5 years under *extreme* abuse (it was always left in my car, well below freezing temps in the wintertime) Originally used strictly as a chess timer (accounting for the other half of it's abuse) As I began to play go, the byoyomi features were discovered by reading the manual. Around $100-$120 (US) the cost hasn't changed, ever. Well worth the price for all the flexible options. -- Joshual000

There is a (DEAD LINK) [ext] comparison on between the Chronos and the 2 DGT timers. It focuses more on chess than on go, but also more on ergonomy than on chess, which makes it interesting regardless. -- uxs

(Wayback machine link)[ext] It's not comparing to the DGT 2010 though.

The Japanse byo-yomi can be simulated in the DGT XL clock by programming a first period "Time" combined with a second period "Bronstein". The DGT XL has the option to store 5 individual user defined settings, so byo-yomi preferences can be used.

HermanHiddema: I've tried this and it simply doesn't work. Programming two periods, one "Time", one "Bronstein" was suggested to me as well, by DGT. I found that when one player enters his "Bronstein" period, the other does so as well. He does not lose his left over time, but he does get free time for each move. So one player is now held to eg 20 second per move. If the other still had 10 minutes left, he now has 10:20 left and gets 20 second free on each move.

blubb: At the official DGT (DEAD LINK) [ext] buglist, that problem is listed as fixed. According to the manual, it should be possible to put up to 4 real byoyomi periods after the initial time period. Each byoyomi period would consists of Bronstein timing with e. g. 20 seconds delay per move and 0 main time, or canadian time with just 1 stone per period. I don't own a DGT XL by myself, but maybe someone with a late enough version could try it out and give us some feedback?

Dave: I just bought a chronos, love it, and have never even seen a DGT, so why shouldn't I contribute to a comparison of the two :-). See the chronos manual page for comments on some of the modes available that are particularly good for Go. Beyond that I would add that the chronos displays 6 digits. I have not seen this remarked on elsewhere but from the pictures of the other clocks, including the DGT, they seem to be more limited. If this is so, then the chronos may be the only one that will display hours, minutes, and seconds when you set out to duplicate the 40 hour limits used in Honinbo Shusai's retirement game against Kitani Minoru (not to mislead anyone there is only one mode on the chronos that allows you to set the main time to more than 10 hours, one of the Japanese byo-yomi modes). Seriously though, the wide display enables some interesting modes. Here is a picture of the chronos counting down a 60-second delay in the early stages of a 9-hour main time game. Even the chronos can not display 5 digits of time, 2 digits of delay time, and a space in the middle (that would be 8 digits). What it does is abreviate the main time, showing hours and minutes only, while the delay is counting down then automatically shifting to full display as the delay drops to zero. Meanwhile the inactive player sees the full remaining time. How do other clocks handle things like this?

ethanb: The Meijinsen can do up to 99 hours in any time mode. It doesn't display seconds during main time though.

Byo-yomi on older DGT Clocks

tealeaf: I own both a DGT XL and a Chronos that were bought for a local Go Club. I'd like to add that while the DGT XL does support Canadian byo-yomi, you still have to keep count of the moves and manually reset the time by holding down one of the buttons. This is true, according to the manual, for the other DGT clocks that support Canadian byo-yomi.

The Chronos clock, by comparison, keeps track of the number of moves made and will reset the time automatically according the settings that you program. I find this far more convenient and, especially considering that the Chronos also supports Japanese byo-yomi, consider it a major advantage for the Chronos over the DGT for Go players.

Bass: Automatic Canadian may be considered an advantage, but I can assure you from personal experience: there will be a very steep price to pay if you mistake your byoyomi starting beep for one of the beeps with which the clock has been showering your slow playing opponent.


Alejo: Finally, I received the Excalibur Game Time 2 and started playing with it. I'm still surprised it overpasses my expectations. I'd heard it's noisy, but it's less noisy than when I place a stone on the goban.

It's got 10 Go time presets:

  • Japanese: from 30m 1stone/10 seconds to 90m 1st/30s.
  • Canadian: from 30m 5st./30s. to 90m 10st./20m.

And the possibility to define another 5 time set. Personally I've added some of the ones I find during online games... I bought it from the USA at Chess Books from Europe, it costed $36 including shipping to Spain and took 15 days to reach home.

See also

Clocks last edited by brose on July 18, 2023 - 20:21
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