Archive 12


Brain Twisters 44

207, MD

Today we would like to offer you the brain twisters series (Die harte Nuß) by Anton Stadlhofer. Anton is presenting one position per week in the German computer forum CSS. As his brain twisters always had a majour echo we thought it would be nice to present them on our page too along with a database for all positions published till now. Many thanks to Anton for sending us his database. We hope you enjoy those positions. You can download the entire database here.

Here you can see the latest diagramm

[Event "ICCF, Russian Championship 5, Kh1"]
[Site "?"]
[Date "2007.??.??"]
[Round "?"]
[White "Shevchenko, Maksim Alekseevich"]
[Black "Razumikhin, Andrey Mikhailovich"]
[Result "1-0"]

r3q1k1/1b1nr1p1/5bR1/p7/1p1PpN2/1N2B2Q/PP5P/3R2K1 w - - 0 0

1.Kh1!! Nf8 2.Rxf6 gxf6 3.Nc5 Bc8 4.Qh4 Nh7 5.Nh5 1-0

Test your favorite engine...


206, MD

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Fix your eyes, get a pair of spectacles or eye lens. Protect your eyes.

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205, MD

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HHdb IV released

204, MD

Dr. Harold van der Heijden (1960 - ) has released a new version of his famous Endgame Study Database IV on October 2nd 2010. Many thanks to him for sending us a free version of his database and allow us to use parts of the information contained on his webpage for writing this review. The current version of the database contains not less than 76132 (48917 win / 27215 draw, 6451 authors, 17348 sources ) chess endgame studies which is about 75% of all chess endgame studies ever published worldwide. These are 8441 studies more than in HHdbIII which appeared in 2005. The solution to many studies has been corrected, enhanced and updated. This database is a playground for all study enthusiasts, problem composers, turney judges, publishers and of course engine testers. It is the biggest and most accurate database available in this field. My review is done using the Arena GUI. Previous versions of the Endgame Study Database contained:



Looking at the studies, solving them, following the solutions, chosing the best studies, testing engines is a very addicting task. It is fun but you really can't stop doing it. You can do this for ages, this is a kind of a life time task even if you look only at your favorite problems and composers.

The database comes in PGN (Portable Game Notation) format so it can be used in almost every chess GUI or PGN reader. It contains studies of great chess composers like: André Chéron, Alexey Alexeyevich Troitsky, Iuri Akobia, Genrikh Kasparyan , Henri Rinck, Yuri Lvovich Averbakh, Harold van der Heijden and many others.

More information about the PGN (by Steven J. Edwards) format can be found here.

An endgame chess study is a chess puzzle where the solver/engine is asked to find a solution to a stipulation like "white wins" or "white draws". Those puzzles have a unique solution. Many of those studies are very difficult for solvers as well as for engines. Chess composers can check whether their idea has already been published. Judges can check new studies comparing them with those contained in the database. All in all a very helpful tool for all professional composers or amateurs and enthusiasts.

Chess endgame study solvers will be delighted to hear that all sublines from the gigantic book 1414 Fins de Partie (1950) of Henri Rinck have been added in the current version of the database, while in HHdbIII in most instances only the main line was given. That is useful, because CQL allows to search for patterns in sublines. Chess Query Language (CQL) was designed to allow researchers, authors, and players to search for games, problems, and studies that match specific themes. You can look for castling, underpromotions or different other maneuvers. It was invented by CQL Lewis Stiller and Gady Costeff. VisualCQL by Ing. Emil Vlasák can be used to querry the database . More information on how to use CQL can be found here.

Also, many endgame study enthusiasts reported thousands of cooks (wrong/impossible/several solutions) in studies to Dr. Harold van der Heijden. Even software has been used to systematically check every sub-7-man position of the main line in the corresponding EGTB, and the results have been kindly supplied for implementation in HHdbIV. Probably all incorrections (where Black is able to refute the stipulation) in sub-7 man positions have now been included in the database. Of course, unsoundness of other endgame studies is an ongoing issue. Also as a major improvement of HHdbIV the sources of corrections, modifications or versions have been added as text before the 1st move of the solution. The same goes for the cooks, including the names of the person(s) who cooked the study (and the relevant move is marked with his initials). This information is relevant for people writing about endgame studies. Without HHdbIV it is almost impossible to figure out where a certain correction of a study was published, or who managed to cook it. Other details/corrections:



You need to be aware of the following abbrevations when looking at the studies in the database This might look difficult at first but afer a while you will have no problem doing so. The codes are the same as in HHdbIII and also HHdb II and include the ability to identify cooks, corrections and other relevant properties of the endgame studies:



All positions in the database can be recognised using the GBR code. The GBR code is a sytem of representing the pieces on the board in a chess position and is used in chess publications for classifying and indexing of chess endgame studies. The name GBR code comes from the code inventors: Richard Kenneth Guy, Hugh Blandford, John Roycroft More information on how this works and its advanteges and backdraws can be found here.

Here are a three studies from the database I have chosen for you: The first is by A. Troitzky, you should try it without tablebases loaded, White to move and win. The second is by G. Kasparyan, the stipulation is white to move and draw. The third by H v.d. Heijden the author of the database, it's white to move and win.

You can order the database here. The database costs € 50. Upon paying you will revieve a code to download the database. The size is 12 Mb (44.5 unzipped). We are sure you will have wonderful hours using this product.





Rybka wins 18th WCCC


203, MD


Rybka (Vasik Rajlich) has won the 18th WCCC in Kanazawa (Japan) (September 24th - October 2nd 2010) ahead of Rondo (Zach Wegner) and Thinker (Kerwin Medina ). Rybka has also won the title in the blitz competition ahead of Shredder (Stefan Meyer-Kahlen) and Jonny (Johannes Zwanzger). More informations can be found at the ICGA info page and a later point at Mark Weeks homepage.

Congratulations to the winner, runner ups and all participants. You can use the free version of Rybka 2.2n under Vasik Rajlichs favorite GUI Arena.





Talk Chess Forum


202, MD


A posting made by me as an answer to Mr. Milos Stanisavljevic in the CCC forum has been deleted by one of the moderators there. It was about his chess engine(s) SB and the SMP version SBs not working in Arena. It is astonnishing that the same doesn't delete obvous personal attacks and accusations made by the Chess Base sysop Harvey Williamson. So the only way to read the truth about corrupt sysops and bugs in chess engines and GUIs is to read the news section of the Arena page.







Update: Mess Mephisto 1.38c


201, MD


Many thanks to Ralf Schaefer for the update of his Winboard adapter for dedicated chess computers. Now the following computers are supported within the Arena interface:



All you need is the MESS program and the corresponding ROMs of the mentioned chess programs. The latest version of the program 1.38a without the ROMs is available here. More information about this topic can be found in this German forum: The intersting part of the thread concerning the Winboard part and describing the parameters starts at page 35.







Mephisto Glasgow/MM IV/MM V/Mephisto Rebel5/Dallas/Amsterdam/Roma under Arena


200, MD


Many thanks to Ralf Schaefer for the update of his Winboard adapter for dedicated chess computers. Now the following computers are supported within the Arena interface:



All you need is the MESS program and the corresponding ROMs of the mentioned chess programs. The latest version of the program 1.38a without the ROMs is available here. More information about this topic can be found in this German forum: The intersting part of the thread concerning the Winboard part and describing the parameters starts at page 35.





Arena/Remote Engines


199, MD


Øystein Johansen has sent me a description on how to use an engine on a remote Linux computer. If you have any questions or feedback please contact me or him so we can improve this manual. Many thanks for this contribution.


Remote chess engine over ssh using Putty and Arena.


Arena is a good GUI for chess engines and chess servers, and it is a popular choice among chess players to connect to chess servers and analyze games and positions. Arena is only available for Windows operating systems. It is not an open source project, however the free to download and use. It supports connection of both UCI and Winboard chess engines.

Sometimes your Windows computer is only a thin client with low memory and a slow processor which is not really strong for analyzing chess. If you're also supposed to do something else with the computer while analyzing, you find that the chess analysis takes all the resources and everything else is really slow. Of course you can lower the priority of the analyzing process, but you really want the best analysis, don't you? This is especially silly if you have a beast of a computer in the same local network. Say your client is a slow 5 year old laptop, and in your local area network you have a shiny new number cruncher with 16 quad core processors and 16GB of memory running Linux. You still like the Arena interface, and the freedom of being at a laptop computer, but if you could have the number cruncher to analyze the chess games that would be just perfect. In this document I will describe how to set up such solution.

The technologies used are quite common and well tested. Secure shell (ssh) is an well known protocol that has been standard in Linux and Unix environments for many years. Putty is a implementation of a ssh client for windows, which has become one of the most popular choices for connecting to a Linux or Unix computer from a Windows computer. I have tested this setup on several systems, so it should be quite flexible. I guess you even can have the chess engine running on any computer you access, anywhere on the internet, but you may have see problems with slow connections. To be honest, I've only tried in local area networks, but there should not be a problem to sit on the café with a wireless connection and then connect the your linux number cruncher at home.


Secure shell and Putty.


At your windows computer you already have Arena installed. You should then download and install putty at this machine. Putty is a ssh client for windows, which is very popular.  Putty download. The ZIP file containing all the binaries should be a safe choice. Just download and extract these binaries to a folder on your system. For the rest of this document I will assume you extracted these files to c:\putty\ but it may be just as natural to put them in c:\Program Files\putty\.

Then we need to connect to the Linux computer. Start putty by double clicking on the putty.exe file you just extracted. A nice dialog box will appear.



In the Host Name (or IP address) box in this dialog, you simply type the host name ot IP adress of the Linux computer. Of course this computer has to have a ssh server running. If it is not running a ssh server, you can usually install it quite simple if you have administrator right to the machine. Read the instructions for your distribution or search the net. If you don't have a ssh server running, you should talk to the administrator.

Click on the Open button and a terminal window will open and prompt you "login as:". Type your user name and the then type your password when prompted.

If everything is fine you should now logged in to you Linux computer for the Windows computer.


Creating and setting up a key pair.


We have to be able to log in with a key pair instead of a password. We therefor have to create a key pair. This should be created at the Linux computer, and you are currently logged in through putty. At the Linux prompt type:

oystein@thelinuxbox:~$ ssh-keygen -t dsa
Generating public/private dsa key pair.
Enter file in which to save the key (/home/oystein/.ssh/id_dsa): <press enter>
Enter passphrase (empty for no passphrase): <type a password or leave blank>
Enter same passphrase again: <retype password>
Your identification has been saved in /home/oystein/.ssh/id_dsa.
Your public key has been saved in /home/oystein/.ssh/
The key fingerprint is:

If everything is fine you should now have a key pair in your .ssh directory. You can check this by typing:

oystein@thelinuxbox:~$ cd ~/.ssh
oystein@thelinuxbox:~$ ls -l
-rw------- 1 oystein oystein 672 2010-05-03 20:11 id_dsa
-rw-r--r-- 1 oystein oystein 610 2010-05-03 20:11
-rw-r--r-- 1 oystein oystein 442 2010-04-06 16:42 known_hosts

You need a file called authorized_key in this same directory that contains the public keys that can be used for logging in. This can simply be done with concatenating the authorized_keys file with like this:

oystein@thelinuxbox:~$ cat >> authorized_keys
oystein@thelinuxbox:~$ ls -l
-rw-r--r-- 1 oystein oystein 610 2010-05-03 20:16 authorized_keys
-rw------- 1 oystein oystein 672 2010-05-03 20:11 id_dsa
-rw-r--r-- 1 oystein oystein 610 2010-05-03 20:11
-rw-r--r-- 1 oystein oystein 442 2010-04-06 16:42 known_hosts

You must then change the file permissions for the authorized_keys file.
oystein@thelinuxbox:~$ chmod 600 authorized_keys

You have now got the necessary key pair on the Linux side, we now need to copy the private key to the windows computer. You need to start a windows Command Prompt window. You can usually start this from the Windows menu. Click: Start -> All Programs -> Accessories -> Command Prompt. The Command Prompt will open, and you can type:

C:\Documents and Settings\oystein\> cd c:\putty

You should now use secure copy (scp) or pscp as it is called in the putty distribution. I will use my username (oystein) and my host name (thelinuxbox) in the example. You must of course use your username and host name or IP address.

C:\putty> pscp oystein@thelinuxbox:/home/oystein/.ssh/id_dsa .

Note the . at the end.

Note: I've experienced that you can not use ~ instead of /home/oystein. It looks like you have to type the full path of the key.

Type the password when prompted, and you will see a output like this:
id_dsa                    | 0 kB |   0.7 kB/s | ETA: 00:00:00 | 100%

Now start puttygen:
C:\putty> puttygen



Click on the Load button, and change the file type to: All files (*.*). Select the id_dsa file which you have just secure copied from Linux, id_dsa, and then press Open. A message box should then give you a notice that the import was successful. As it says: To use this key with putty, you need to save it in Putty's own format. After closing the message box, click Save private key button and select a good filename. It's recommended to use the .ppk extension. A good filename can therefore be id_dsa.ppk. After saving, you can close the window.

Note: For the sake of security, it is recommended that you delete the id_dsa file that was secure copied from linux on the windows system. You really don't need it on the Windows system anymore, and if someone gets it they sure knows how to take advantage of it. So, my clear advice is to remove this file after you have saved the .ppk file.

Putty uses a agent system to handle key pairs. The agent is called pagenat. Before you start any remote connections you should therefore run the agent and load the key into it.

C:\putty> pageant

Nothing appears to happen, but if you look in your system tray you see you got a little icon of a computer wearing a hat. Right-click this icon and select the Add Key menu item. Find the id_dsa.ppk file you have generated and select it and press Open. If you selected a password when you created the keys on the linux machine, you will be prompted for this password.



If you now again right-click the pageant icon, and then select View Keys, you will see that your key is loaded in the pageant agent. Just close this window.

You are now ready to log in to your linux machine without using a password. Try it out:
C:\putty> putty oystein@thelinuxbox

You should then get a new terminal window to the linux machine, and you should not be prompted for a password. You don't need this terminal window so you can just exit. It's just to test that the key pair and pageant works correctly.


Installing a chess engines on linux.


You now need to install a chess engine on the linux machine. You can compite an engine your self or download an available engine. Any UCI or Winboard engine should work. The choice is yours and you may also install several. For Linux I highly recommend Stockfish. The build by Jim Ablett is really good. For the sake of the example I will use Stockfish as an example.

Just download the zip files form with the Stockfish, unzip it, and place the executable in a directory at the linux machine where it feels natural. If you have administrator rights on the machine you should place it in /usr/local/bin, if not you can place it somewhere under you home directory.

In the stockfish zip file there is both a 32bit compiled version and a 64bit version. It you are not sure if your machine is 32bit or 64bit, you can type:

oystein@thelinuxbox:~$ uname -m

If the response is x86_64 you have a 64bit machine, if it says i686 or something similar, you have a 32bit machine.

Lets assume you have administrator rights to the linux machine and wants to install the executable in /usr/local/bin/. Move the executable to this directory.

oystein@thelinuxbox:~$ sudo mv stockfish-171-64-ja /usr/local/bin
oystein's password: <type password>

For simplicity it's nice to have a symbolic link named stockfish in the same directory, such that you just alter what the symbolic link points to when you install new versions of stockfish.

oystein@thelinuxbox:~$ cd /usr/local/bin
oystein@thelinuxbox:/usr/local/bin$ sudo ln -s stockfish-171-64-ja stockfish

Make sure the file has execution flag in it's permissions.
oystein@thelinuxbox:/usr/local/bin$ sudo chmod +x stockfish-171-64-ja

You can also install a opening book somewhere on the Linux machine. Get the file Book.bin. This file can be installed in /usr/local/share/. (My preference)

oystein@thelinuxbox:~$ sudo mv Book.bin /usr/local/share

Just to make sure that every thing is install you can try to start stockfish on the linux computer.

oystein@thelinuxbox:~$ stockfish
Stockfish 1.7.1 JA 64bit. By Tord Romstad, Marco Costalba, Joona Kiiski.

Yes, it looks like it works at the linux machine. Press Ctrl-C to stop the engine.

The final test before we start using this in Arena is to check that we can start stockfish from the Windows computer:

C:\putty> plink -ssh oystein@thelinuxbox "stockfish"
Stockfish 1.7.1 JA 64bit. By Tord Romstad, Marco Costalba, Joona Kiiski.

Yes, it looks like it works also when connecting through plink. Press Ctrl-C to stop the engine and close the connection. If it didn't work, make sure that pageant is running and your key is loaded.

Of course, if you installed it in a different directory on the linux machine, maybe in your $HOME directory, you should instead type:

C:\putty> plink -ssh oystein@thelinuxbox "~/mychessengines/stockfish"
Stockfish 1.7.1 JA 64bit. By Tord Romstad, Marco Costalba, Joona Kiiski.


Configuring Arena.


Hopefully you have installed Arena on your Windows machine. If not, please visit Arena's website. Start up Arena as you usually do. In the top menu, select Engines -> Manage and then press the New button. You will get a file dialog box where you're supposed to select a native engine. Instead you select plink.exe from C:\putty. In the next dialog you must state if this is a UCI or Winboard chess engine. Select the proper option. For stockfish it should be UCI. I get a PLINK engine listed in the list of engines. In the General tab, you can change the name to something more appropriate than PLINK, let's call it "Stockfish (Linux 64bit)". Put in the authors names in the next entry box, but leave "C:\putty\plink.exe" in the Command Line entry box.

In the Command Line Parameters you should add: -ssh oystein@thelinuxbox "stockfish".
The Engine management dialog should then look like this:



For using the opening book, you can load that through the UCI dialog box. In the Arenas Engine menu select the engine specific menu, like "Engine 1 / Stockfish Linux 64bit" and then select the Configure option form this sub menu.

In the Book File entry you can add the engine book. Remember that this is the linux environment path, such that you should type in /usr/local/share/Book.bin. Like this:



As you can see, you can also set any other UCI option in this dialog.

That's it! You should now be able to use the engine running on the Linux machine and having just the the Arena interface running at the windows machine. Good luck in your games!

As a closing note: This method of running engines is not limited to Arena and and Linux. You can probably run the engine on any other system that has a ssh server running. It is probably possible to use an other interface than Arena also. It is even possible to run other things than chess engines through secure shell. (You can even have X Windows based applications running over ssh). Try for example: plink -ssh oystein@thelinuxbox "cal" and the calendar program will be executed on the linux machine.

If you have any questions or comments, you may contact me at





At a later point this engine will be included in the Arena setup.

Many thanks to Ralf and Volker.