Komodo 9 FAQ

What is Komodo 9?

Komodo 9 is a chess engine program. It searches and calculates the moves of the chess game. Komodo 9.3 is the latest version. It is developed to work on MS Windows, Linux, OS X and Android (available at https://play.google.com/store/apps/details?id=com.komodochess.komodo9) operating systems. The Komodo 9 series is optimized for multi-core computing. The program’s evaluation is developed by a Grandmaster.

How it works?

The copy you received comes without the graphical user interface (GUI) or ‘chessboard’ where you can see the chess match in progress.The Komodo web site suggests a few 'chessboard' programs (aka GUI) which can be used with Komodo. Some of the GUIs are open source and of very high quality. The most commonly used are Arena Chess (free), Chessbase (pay), Fritz (pay) and Aquarium (pay).  If after checking out these links you need more help and installation troubleshooting, please email komodochesshelp /at/ gmail dot com

Do I need subscription or single copy?

Starting in July 2015, we offer our customers an annual subscription at a higher price. Regular updates are provided for subscribers. The team works hard to publish updated versions when we add important features or enough elo gain. Optionally, you can get a copy of the most recent version for a lower price.

How to order?

You can order Komodo 9 through the website (komodochess.com) or through our distribution partners. Currently, Komodo Chess accepts payments only through PayPal. If you are in a country that is not being serviced by PayPal, we have no other methods oforpayments. Please follow these steps to order:

For Windows, Linux and OS X versions:

  1. Create an account with the Komodo website. Since hotmail.out, live.com and outlook.com often block emails from our site, we suggest using another email address.
  2. Log in to your newly created account
  3. Order and pay your copy of Komodo 9 with PayPal.
  4. Check your email for a link to download the file.

For Android version:

  1. Go to the  Google Play store to buy Komodo.
  2. After purchase, select your devices to install the Komodo App.
  3. You will also need a chess GUI. SOme good ones are listed on this page: http://komodochess.com/Komodo_Play_Store_Instructions_9.html

What files do I receive in the download bundle?

Your downloaded copy has an executable file for Microsoft Windows and binary files for Linux and OS X. You can find the files in the respective directories or folders. Please note that the bundle is compressed and you might need the appropriate program to decompress it. Recent versions of Windows can already handle this.

The Android version is distributed only through the Google Play store.

What is the difference between the Windows, Linux and OS X versions of Komodo 9 and the Android version for mobile devices?

The same code base is used for all platforms.  The Android version has smaller default memory sizes since Android devices are generally more limited than PCs.  Windows, Linux and OS X versions of the program are optimized for use on multi-core systems.

Why did I not receive a copy after my payment?

Normally, orders are processed immediately and the system sends automatically a download link for Komodo 9. However, emails generated automatically by the order processing system are sometimes flagged by mail servers as spam. If you have already purchased a copy and you are still having problems with not receiving up to date information from us, we can manually re-set your account email. Please feel free to contact us at komodochesshelp /at/ gmail dot com.

Currently, a well-known issue is present with the spam filtration system of of Microsoft’s mail servers (Outlook, Live, Hotmail). We recommend that you use email address other than the ones offered by Microsoft to set up your account with the Komodo website. You should also ensure komodochess.com is not  being fitletered by your email systems so you can receive the program.

Customer Loyalty Discount

Customers who have bought the previous version (Komodo 8) are eligible to receive 20% discount on future orders.

Licensing and Verification

The copy you received is licensed to you personally. You are free to use it on all machines you personally own, but not  on other machines. We also reserve the right to suspend accounts to customers who have abusively distributed illegal copies of the Komodo chess engine’s current and previous versions, without refund. We also reserve the right to be more generous to customers who have been supportive of our team and have notified us about websites and people distributing illegal copies. It is our joint efforts that make the world a better place!!!

Why does my antivirus program detect Komodo Chess engine as a virus?

The download bundle is a .zip file and contains the executable and binary files. Some antivirus programs detect executables and binaries as viruses. Please read your antivirus program manual to resolve the issue. There is a possibility to tell most programs to consider the file as safe.

Why do I have troubles with my GUI loading the Komodo engine Linux or OS X binary file?

Linux and OS X might need you to change the permissions of the Komodo 9 binary files.

For the Linux distribution, you can right click on it and change the file permissions in your graphic interface file finder. You can also do that by executing the command in a terminal window or a console:

$ sudo chmod +x /path/to/komodo-9.3-linux*

For OS X you can change the file permissions by opening a Terminal window in the App folder. There you can type in the command:

$ sudo chmod +x /path/to/komodo-9.3-64-osx

How to change the settings of Komodo?

The GUI chess board program allows you to change the basic settings for the Komodo engine.

How can I change the additional settings of Komodo to fit my specific machine hardware and time controls?

In the .zip file you downloaded you can read the instructions in the file setHash.txt. In case you need further assistance, please contact us via email komodochesshelp /at/ gmail dot com.

What is Komodo’s Table Memory?

This parameter determines how much memory, in megabytes, Komodo will allocate to various internal tables such as the pawn structure hash table, evaluation cache and others.   The default value is 64 MB. It is probably close to optimal for fast play on most machines cira 2013. If you allocate too much memory it can negatively impact your performance and if you allocate too little it can also negatively impact your performance. Our team encourages you to experiment with lowering (or raising) this value if you use an entry level machine or a particularly high performance machine. For slower games (or analysis) and/or for machines with many cores, higher values are appropriate. We have raised the upper limit in Komodo 9.3 to 1024 megabytes since this may be appropriate for TCEC or similar use with many cores and long time limits.

What is Hash?

Hash defines the maximum amount of memory to be used for the transposition table - a major factor in the performance of modern chess programs. The default amount is set to 128 (in megabytes) which is probably more than adequate for standard use.

However, see the document setHASH.txt in the .zip bundle for more specific information on how this should be set for ultimate performance. All 64 bit versions allow up to 65536 megabytes (64 GB) to be allocated, assuming your system has that much memory. The Windows 32 bit version limits this to 2048 megabytes due to hardware and operating system limitations.

Note: Komodo’s hash entry size is a bit different from other programs. If you allocate 16 megabytes, Komodo will only use 12, and not use any more until you set it to 24, and so on with each doubling. This is normal.

Persistent Hash

This feature is useful for long analysis.  It allows you to save the current Hash Table to your hard drive and reload it later.  First, set a name for the file in the "Hash File Name" option. Most GUIs will require you to close the dialog box with an OK to “set” the name. You should then stop the search/analysis and return to the UCI parameters. Then click the "Save Hash to File" button.  To reload the saved information, first make sure the "Hash File Name" is for the file you want and click "Load Hash from File". Once it loads, you may continue the analysis. You must make sure the current hash filename is exactlt the same the one used when you saved the file.  

Note: Hash files can be very large and can take a lot of time to save and load. Please make sure you have enough disk space to use them.

What is Use LMR (Late Move Reductions)?

LMR is a search technique for aggressive pruning of moves in the search tree. The result is much deeper depths. The risk of using this technique is that sometimes Komodo can miss important moves.  The engine gives you the option to turn this on or off. This feature is useful along with the reduction parameter.  In general Komodo will play much stronger with this option turned on. In some positions a much shallower but more thorough search might be advantageous. If you consider that this is the case, you can turn this option off. Results are always best achieved with experimentation with the engine’s parameters.

What is Null Move Pruning?

This parameter is similar to LMR. It allows for aggressive pruning of moves from the search tree.  Komodo can be a much stronger engine with this option turned ON. The risk of using it is that occasionally Komodo might miss on very deep threats or zugzwang positions.  We encourage you to experiment in case you are in a difficult position which cannot be resolved and want to see if a much shallower, but more thorough, search would help.

What is Reduction?

This control determines how deeply Komodo searches.  Higher "Reduction" values will cause Komodo to reduce parts of the search tree faster. This will increase the overall search depth but possibly miss on some good moves. The default is 0. We are fairly confident that the best value on a single thread is close to zero, but we have not yet determined whether other values may be better on many threads. Please feel free to experiment and report back to our team for discussing results.

What is Selectivity?

The Selectivity parameter adjusts the number of moves Komodo prunes.  Higher values will encourage Komodo to prune more moves at low search depths, leading to a deeper overall search at an increasing risk of missing some moves. The default value is 74. We do encourage you to experiment with your machine. Please feel free to report results.

What is King Safety?

This parameter controls how highly Komodo scores king safety.  The higher the value, the greater the effects of attacks on the king in Komodo's evaluation. The default value is 60.

How many Threads does Komodo use?

The default number of Threads is 1. For multi-core machines you will want to change this value.  For ultimate performance we suggest setting this to the number of "real" cores on your machine.

For example, on an i7 with hyper-threading, you typically have 4 "real" cores and 4 hyper-threaded or virtual cores.  The operating system will probably report 8 cores but we recommend setting Komodo for 4 threads in this case. If you find yout GUI is sluggish in responding using all the cores on your machine, we recommend lowering the Threads value by 1. This frees up one core for use by the operating system and GUI.

What is Time Usage?

Time Usage allows to manipulate Komodo's time control heuristics, to make its allocation either more aggressive or less aggressive. This value and Overhead ms can help compensate for a slower internet connection during online play, or a slower GUI. The default value is set to 0 which is what we believe is the ideal setting but remains to be tested.  You can make it play faster by assigning a negative number or you can make it allocate time more aggressively by setting it to a positive value.  The range of values is between -9 and +9.  It's very unlikely extreme values will have positive effect on the quality of the engine performance. We suggest experimenting with relatively modest changes to the default.

What is Overhead ms?

The Overhead ms parameter compensates for slow user interfaces or slow internet connections. In such situations a fraction of a second can be lost in the processing and transfer of information back and forth from engine to interface.  The value is in milliseconds (1/1000th of a second).  This should probably be left at the default value unless you see the program starting to forfeit games due to exhausting its time. If you see such time forfeits, increase this value. The default is set to 30 milliseconds. For internet play where lag is an issue a value of 60 is a good first try but might have to go as high as 100 ms or more.

What is Drawscore and how to set it (Komodo 9.1 and earlier)?

In some programs this parameter is called the "contempt factor". It defines the value of a draw. The default value is set to -10 which means that the program will have a slight tendency to avoid a draw (even if its position is slightly worse). A value of -100 would cause Komodo to avoid a draw unless it was at least a pawn down. A value of 100 would cause Komodo to seek draws unless it was at least a pawn ahead. In the endgame Drawscore is automatically brought closer to zero since the chance of winning from a slightly inferior position is much lower in the endgame. Note Komodo 9.3 has replaced Drawscore with a new Contemp, documented below.

What is Contempt (Komodo 9.3 and newer)?

Contempt is added to the computer’s evaluation to try and discourage piece trades and repetition draws early in the game. The default value is 15 which should help against weaker opponents. Against near-equal opponents, set Contempt to zero for best results. Against a human opponent, contempt should be at least 25 even if he is World Champion. Suggested values include 40 against grandmasters, 50 against masters, and 75 against strong amateurs. Higher Contempt values are especially appropriate when Komodo is giving a handicap.

Note: For handicap play, a good rule of thumb is to set Contempt for half of the value of the initial position based on a one minute search in infinite analysis mode. For example, when giving knight odds, set Contempt to 175, which is 175 centipawns, or half of the disadvantage. The determination of the disadvantage can be estimated through an initial one-minute analysis search, which for this example shows Komodo as down by 3.5 pawns (350 centipawns).

Does Komodo support Tablebases or ‘Syzygy’?

Komodo supports Ronald de Man's 'Syzygy' endgame tablebases. Endgame tablebases can be used to provide absolute knowledge about chess positions in which only a few pieces are left on the board (at the time of this writing, the Syzygy bases support up to 6-man positions [including the kings]). Please refer to the README file on how to use the Syzygy endgame tablebases.

How to get the ‘Syzygy’ tablebases?

At the moment, the best way to get the required files is via the file-sharing service BitTorrent (on OSX, Transmission is a good client, on Windows and Linux, Vuze).  The necessary .torrent files can be found at http://oics.olympuschess.com/tracker/index.php. You should get at least the 3-4-5-man set (approx. 2 GB). The 6-man set is an additional approx. 138 GB large and will take a while to download. The 3-4-5-man set is also available for direct download from: