November 9th, 2014

Arasan played in a couple of tournaments on H.G. Mueller's winboard.nl server this weekend. One was the annual CSVN Open Internet Tournament. In this tournament, Arasan reached the following position in its game against Goldbar:

This is truly a terrible position for White, because not only is the King on the worst square to be on in the endgame (h1) but it is stuck there: because of the enemy piece positions, it cannot move even one square. After this game, I implemented another scoring term, which penalizes low king mobility in the endgame. Testing showed that this is overall an improvement, although due to the horizon effect, scoring changes will never fully prevent falling into this kind of position.

This example shows that, while automated testing is valuable, watching the program play and using some chess sense is also very useful in finding improvements.

Next weekend Arasan is entered in the CVSN Programmers' Tournament in the Netherlands. It will be operated remotely by Tessa Pilj, the daughter of fellow chess programmer Richard Pilj.