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        Arimaa >> General Discussion >> Silver to play and win in four
        
(Message started by: browni3141 on Nov 2^nd, 2012, 12:46am)

Title: Silver to play and win in four
Post by browni3141 on Nov 2^nd, 2012, 12:46am

http://arimaa.com/arimaa/notconv/old/boardimg.php?orient=g&size=314&imgtype=jpeg&ranks=2c3R/1r5R/rD3RRD/r5R//1d1E/r1r1deR/2rCrR
Ignore that the board isn't oriented right. This is from the gold perspective.
I haven't checked for faster solutions, but I'm fairly certain that my analysis was correct and that there is indeed a goal in four. Post the solution (or a faster one), so that the text is not visible.
The game: http://arimaa.com/arimaa/gameroom/comments.cgi?gid=248554

Title: Re: Silver to play and win in four
Post by aaaa on Nov 2^nd, 2012, 6:11am

Nice find. I can confirm the correctness of the goal in 4 and tell that there is nothing faster. You might want to add it as a puzzle (http://arimaa.com/arimaa/puzzles/make.cgi).

Title: Re: Silver to play and win in four
Post by Fritzlein on Nov 2^nd, 2012, 8:33am

on 11/02/12 at 00:46:33, browni3141 wrote:

I haven't checked for faster solutions, but I'm fairly certain that my analysis was correct and that there is indeed a goal in four. Post the solution (or a faster one), so that the text is not visible.

My attempt:
14s eb3e ec3x Ra3e ra4s ra3s
15g Ec5w Ca5s Eb5w Ca4s
15s Rb3e Rc3x db4s Ca3n db3w
16g Ca4e Ea5s da3e Ea4s
16s dc7s dc6s dc5s ra6s
17g db3e Ea3e Rb2e Eb3s
17s dc3w dc4s db3w dc3x ra2s

If I have it right, I'm very impressed that you found it. Thanks for sharing!

Title: Re: Silver to play and win in four
Post by browni3141 on Nov 2^nd, 2012, 8:55am

You are correct Fritzlein. Is every move in the solution a unique winning move, or just the first one? Certainly the goal in 2 move is unique, and the goal in three move almost certainly is, but it's still nice to have bot verification. It is even better if every move is unique.

Title: Re: Silver to play and win in four
Post by aaaa on Nov 2^nd, 2012, 9:16am

The goal in 3 is unique.

Title: Re: Silver to play and win in four
Post by ChrisB on Nov 2^nd, 2012, 10:53am

Nice problem!

I missed gold's final move (which makes silver's win even cooler), but otherwise came up with the same moves as Fritzlein.

Title: Re: Silver to play and win in four
Post by browni3141 on Nov 2^nd, 2012, 1:28pm

I only wish that I will have the change to spring such a move on an unsuspecting human opponent :)
When I think of being on the receiving end of such a tactic, I imagine dread as I see the opponent's elephant fall into the trap.

Title: Re: Silver to play and win in four
Post by clyring on Nov 2^nd, 2012, 4:09pm

Getting a rabbit that can't be blocked, especially on a2, should always raise a few red flags- I am reminded of a similar idea employed in a certain postal game. (http://arimaa.com/arimaa/gameroom/comments.cgi?gid=234733)

Title: Re: Silver to play and win in four
Post by browni3141 on Nov 2^nd, 2012, 5:32pm

on 11/02/12 at 16:09:54, clyring wrote:

Yes, the only problem I see with this puzzle is that the most obvious move is also the correct one. The other moves are trickier though.

Title: Re: Silver to play and win in four
Post by Hippo on Nov 4^th, 2012, 2:53am

Hmm, the goal on depth 4 is far away from bot's horizon that even looking one turn further in narrow coridor's does not help. May be some kind of proof number search extension would help here. ... it is deep in my todo list as well.