The Checker Maven

KingsRow Digs Into the Last of the "Lost" 3-Move Ballots

In the 1930s, the 3-move restriction style of play was introduced as a follow-on to 2-move restriction and the earlier go-as-you-please (unrestricted) play, in order to hopefully "energize" tournaments and reduce the number of drawn games. Leaving out duplicates and immediate losses, there are 174 possible 3-move ballots; initially, 137 of them were considered "playable."

Over time, that number went up to 144, and recently, 12 additional ballots have been added to the deck (see Richard Pask's book, The Golden Dozen, available for download on this site). Now, openings formerly thought to be overly one-sided, such as the Skunk, the Black Hole, the Twilight Zone, and others, are being seen in high-level competition.

This still leaves 18 ballots believed to be unplayable. But Ed Gilbert, author of the world-class KingsRow computer checker engine, is doing deep automated analysis to test this assumption.

Having recently completed calculation of a 10-piece endgame database (some 250 or more gigabtyes in size, including every possible position with 10 or fewer pieces on the board), Ed thought that intensive "book" analysis was the order of the day. After all, computer analysis, (along with skilled human analysis, of course) was a major factor in bringing the latest 12 ballots into play. Could there be hidden secrets in the remaining 18 ballots still thought to be a loss?

Ed expects book analysis of these last openings to take a few months. He doesn't necessarily expect to find that one of these is indeed playable, but he'll know the answer one way or the other in due course.

Ed explains his procedure and motivation as follows, with an interesting reference to Italian checkers: "I set up a computer to work on a book for the 18 'lost' ballots with KR 10 (KingsRow with the 10-piece database). I will let it run until all are confirmed lost. The reason I started this is that I just finished the 9-piece and partial 10-piece databases for the Italian game. What I found interesting is that I played out the 9 Italian ballots that I had labeled as probable losses, and in one of them it dropped out of book and instantly showed a database draw! I probed some of the other 'winning' attacks and think I might have found a draw for another one. I will have to build books to really confirm this, but it's possible that the 8-piece book was wrong about some of these lost ballots. Wouldn't it be neat if something similar happened with English checkers? If course I have already played out the 18 lost ballots with KR10 and did not find any obvious draws, and I think it is a lot less likely." (Playing out a position is a less conclusive but faster type of analysis than building a book.)

KingsRow Author Ed Gilbert

Ed followed up later: "The book generator has only been working for about 3 days, but already most of the lost ballots have scores around 90 (meaning they are indeed losses). While it will probably take a couple of months to fully complete this job, if there are any that have drawing chances I may know much sooner than that. There are three left that still have low scores--- the Shark, the Cheetah, and the cousin to the Black Widow (12-16 23-19 16-23). While it is not very likely, I am hoping for a draw in one of these!" (In KingsRow, scores approaching 100 are just about certain losses. The lower the score, the more balanced the position. Scores of around 30 show a definite advantage but short of a sure win; scores around 10 or lower are highly likely to indicate drawn positions.)

We'll report further on Ed's results as they become available.

11/12/05 - Category: Programs - Printer friendly version
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