| Below is my solution to the worst move problem.
Worst move: 6/5, 4/3, 2/1(2)
Best move: 16/15*, 15/14*, 14/13*, 13/12*
According to Jellyfish level 7 estimates:
After 16/15*, 15/14*, 14/13*, 13/12*, Blue's equity is +2.003 After 6/5, 4/3, 2/1(2), Blue's equity is -1.680
That's a swing of 3.683 -- quite a whopper of a mistake. However, severalof the contestants were able to do better (worse). The successful entries generally followed the same theme -- both sides having good boards and abunch of blots strewn around the outfield, with the best play scooping up the blots or making a closed board and the worst play a major disaster.
In third place was Julian Hayhurst. His entry:
Worst move: 5/3, 4/3, 2/1
Best move: 10/9*, 9/8*, 8/7*, 7/6
According to Jellyfish: Equity after 10/9*, 9/8*, 8/7*, 7/6 is +2.076 Equity after 5/3, 4/3, 2/1 is -1.733 Total equity swing = 3.809
In second place was Stein Kulseth. His entry:
Worst move: 16/1 6/1
Best move: 7/2 8/3 9/4 10/5
According to Jellyfish: Equity after 7/2, 8/3, 9/4, 10/5 is +1.946 Equity after 16/1, 6/1 is -1.867 Total equity swing = 3.813
And the winner for the worst move of the world is Teppo Salo. Here is his awful play:
Worst move: 5/1, 4/2, 3/1
Best move: 14/12*, 12/10*, 10/8*, 8/6
According to Jellyfish: Equity after 14/12*, 12/10*, 10/8*, 8/6 is +2.067 Equity after 5/1, 4/2, 3/1 is -1.762 Total equity swing = 3.829
I have no idea why Jellyfish thinks any one of these plays is better or worse than the others, but Jellyfish is the referee and its decision is final. Anybody who has any complaints please send them to Fredrik Dahl, inventor of Jellyfish.
It is clear that Jellyfish has a lot of difficulty estimating the absolute equities for these kinds of positions. I can't imagine why -- surely theymust have come up all the time in the training period. I haven't tried rolling them out, but it appears that the backgammon rate for these plays has to be high enough to send the best move equities higher than+2.000 and the worst move equities lower than -2.000. Thus, we may not have determined what the real worst move in the world is. However, perhaps it is time to move on to saner issues. |