KingsRow Italian

KingsRow Italian is a program that plays Italian checkers. It is used with Martin Fierz's user interface program called CheckerBoard. Both KingsRow and CheckerBoard are free programs and can be downloaded using the links below. 

Opening Book 

KingsRow Italian has an opening book database of 906,000 positions. It covers all 174 of the 3-move openings, including 8 which this book shows are probably losses. The book was built by doing systematic searches with KingsRow and the 10-piece database. This technique is called dropout expansion that was developed by Thomas Linke. Martin Fierz has written an overview of how dropout expansion works. You can read it here.

Click here to view a summary table with some statistics on the opening book.

Endgame Databases

I have built win/loss/draw (WLD) and 'moves-to-conversion' (MTC) databases for Italian checkers for positions with up to 10 pieces. 

The WLD db contains the game result for positions with 2 pieces through 9 pieces with up to 5 pieces on one side, and for 5x5 10-piece positions with one or fewer kings on a side. This data gives KingsRow a huge increase in playing strength. During a search, many lines will trade down to positions that are in the db, even when the game position has 20 pieces or more. By propagating these db values back to the game position, the program is able to see the end result from positions very early in the game.

The MTC database helps the program play some winning endgame positions that require very many moves for the win to be consummated (or to defend those positions if it is playing the losing side). It is consulted before each search, but is not used during a search, so it uses very little cache RAM and does not affect the search speed. Some related information about the 10-piece MTC database that I built for English checkers is here. Use of the MTC database is optional. The program will correctly play most endings without it. But if you are interested in seeing the correct play to some difficult endings then you may find that this addition is useful. For example, it shows how to play this ending, which is a black win, but if white defends perfectly it requires 147 king moves before black can force a man or capture move (thus making visible progress towards the conclusion of the game).

 [FEN "B:WK9,K14,K29:BK6,K24,K26,25."] 

The following Italian 8-piece position has the longest moves to conversion that I have found in either Italian or English checkers, including 9-piece and 10-piece English positions. This remarkable position requires 219 king moves before black can force a conversion move. 

[FEN "B:WK7,K9,K24,23:BK2,K1,K8,K15."]

Download a complete list of the longest MTC positions in each database subdivision. You can copy the FEN positions to the Windows clipboard and paste them directly into CheckerBoard. Click here to download.

For programmers, if you have written a program that plays Italian checkers, you can use these 8-piece databases with the driver that I have supplied here. 

Obtaining Endgame Databases

You can download endgame databases for positions up to 8 pieces using the links below. Unzip the WLD files into a directory named kr_ital_wld. To use the 8-piece files, you also need the 7-piece files, which contains data for positions from 2 pieces through 7 pieces. Unzip the MTC files into a directory named kr_ital_mtc.

If you have a fast internet connection, you can download the 9-piece and 10-piece WLD databases using the links below. To use these, you also need the smaller WLD databases described above.

To configure KingsRow for the endgame databases, go to the Checkerboard menu Engine, Options. There is more information in the help file (menu Engine, Help).


Ed Gilbert
Last revised: February 09, 2014.