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        Arimaa >> General Discussion >> A possible tactic to deal with a Horse hostage
        
(Message started by: supersamu on Sep 20^th, 2012, 12:04pm)

Title: A possible tactic to deal with a Horse hostage
Post by supersamu on Sep 20^th, 2012, 12:04pm

Hello all,
I have come up with a way ( I thought of it by myself, i didn´t necessarily invent it) where a player can in some positions deal tactically with a Horse hostage. I don´t know if it is useful (or even comes up in real games), but in my eyes a beginner who heard of this tactic should have an advantage over one who hasn´t heard of it 8) . Here is a position, where this tactic is applicable with gold to move:

1g Ra1 Rb1 Rc1 Dg3 De2 Rf1 Rg1 Rh1 Ra2 Hb3 Cc2 Md3 Ee6 Cf2 Hh6 Rh2
1s ra7 hb6 cc7 ed5 mg6 cf7 hh5 rh7 ra8 rb8 rc8 dd8 de7 rf8 rg7 rh8

Here is a link to the plan window: http://arimaa.com/arimaa/games/planGame.cgi

What should gold play?

Sorry, i wanted to post the answer, but i can´t find the feature to make text hidden. I hope the move i mean is apparent. If the move is not apparent, maybe i overlooked some tactical complications.
I can´t remember if i ever played this tactic, my horse was seldom taken hostage. (And i can hardly think of any game i saw where a horse was taken hostage with the optimal pattern.)
Anyway, what would you play after gold´s (hopefully logical) move?

--------
EDIT: The move aaaa suggested is correct
--------

Title: Re: A possible tactic to deal with a Horse hostage
Post by aaaa on Sep 20^th, 2012, 12:20pm

I assume the solution you're looking for is (in ROT13) gb chyy gur qbt orsber guerngravat gb syvc gur pnzry.

Although the resulting peculiarity of the position is reasonably well-known, I can't recall players deliberately engineering it with this move.

Title: Re: A possible tactic to deal with a Horse hostage
Post by browni3141 on Sep 20^th, 2012, 1:19pm

I see what the best move is. That's a pretty common type of pattern, but usually I just try to avoid stepping into it rather than setting it up. It's common with a horse hostage, but it occurs in more general situations as well.

Title: Re: A possible tactic to deal with a Horse hostage
Post by Hippo on Sep 20^th, 2012, 4:07pm

Hmm so incomplete hexagon pattern ;)

Title: Re: A possible tactic to deal with a Horse hostage
Post by browni3141 on Sep 20^th, 2012, 8:48pm

After gold's move, the first move that comes to mind for silver is ed5s ed4e Md3n de6n, and after everything happens gold gets a slight lead with at least a rabbit pull.
The next move that comes to mind is ed5s mg6w dd8s rf8e, not wanting the hostage to get away so easily, and still hoping to get an advantage from it.

Title: Re: A possible tactic to deal with a Horse hostage
Post by chessandgo on Sep 21^st, 2012, 9:09am

Are we really going to discuss a move without anyone explicitly naming it (for those of us who don't speak ROT13, whatever ROT13 might be)?

If you are all referring to what I think you're referring to, silver can move his elephant to f5. If the rg7 was a non-rabbit piece, Gold wouldn't have a follow-up, so I guess you're worried about Gold pulling the rg7 to g6? I'm not sure whether it's anything more than inconvenient for silver, in any case Silver is still was ahead. Not putting a rabbit on g7, but a piece instead (earlier) is an option if you don't like this move by Gold. I think I've both played that move and been confronted to it (not 100% sure tho).

Title: Re: A possible tactic to deal with a Horse hostage
Post by Fritzlein on Sep 21^st, 2012, 3:39pm

on 09/20/12 at 12:04:11, supersamu wrote:

Sorry, i wanted to post the answer, but i can´t find the feature to make text hidden.

I believe that the color-coding of text, discovered by the community while discussing jdb's endgame puzzles, is as convenient as it gets. One uses

Code:

[color=ghostwhite]
or
[color=lightsteelblue]

depending on whether one's post is even or odd on the page.

on 09/21/12 at 09:09:39, chessandgo wrote:

Are we really going to discuss a move without anyone explicitly naming it (for those of us who don't speak ROT13, whatever ROT13 might be)?

http://www.rot13.com/ will translate for you.

Quote:

If you are all referring to what I think you're referring to, silver can move his elephant to f5.

Nope. It was new to me too, which is why I'm glad for this thread. It took me five minutes to find, which is why I am glad it was presented as a puzzle with a hidden answer. The answer is (select blank space below to reveal)

2g Ee6s de7s Ee5e Ef5e
after which the silver camel can capture the gold horse, but would have to end on f5 and be captured itself.

Clearly, supersamu, this isn't a tactic that all experienced players know and only beginners would benefit from discussing. It is a nice find, and I quite grateful you posted it rather than saving it to spring on me in the AWL!

Title: Re: A possible tactic to deal with a Horse hostage
Post by browni3141 on Sep 21^st, 2012, 4:05pm

on 09/21/12 at 09:09:39, chessandgo wrote:

I'm not really sure that I get these moves. How does the hostage have any value if the elephant has to defend as well? After gold pulls the g7 rabbit things don't look so good for silver in my opinion. I don't see how silver can hold onto the horse hostage since gold is "threatening" 4g Eg5s hh5w Hh6s Hh5s, and even if he could keep the hostage, I'm not sure silver has enough time to make use of it.

Title: Re: A possible tactic to deal with a Horse hostage
Post by Boo on Sep 22^nd, 2012, 2:43am

Silver can play e-->f5, c-->f6, ra7->b7 not allowing rabbit pull to g6 and threatening to play rf7 rg7 Hh7 mh6 which would imprison the horse until some time later (when silver has created a second threat).

Title: Re: A possible tactic to deal with a Horse hostage
Post by chessandgo on Sep 22^nd, 2012, 5:25am

Do we agree that, if the rg7 and cf7 were inverted in the starting position, then (seriously, can't we just plainly write the moves?)

2g Ee6s de7s Ee5e Ef5e
2s ed5e ee5e cf7w

woulnd't help Gold? And even as the position stands (and once again, if silver doesn't like it, why put a rabbit on g7 in the first place and not a piece?), is

2g Ee6s de7s Ee5e Ef5e
2s ed5e ee5e cf7w dd8s
3g mg6w Eg5n Eg6s rg7s
3s mf6n mf7e rg6w mg7s

really better than the starting position for Gold?

Title: Re: A possible tactic to deal with a Horse hostage
Post by blackczajk on Sep 22^nd, 2012, 8:56am

Since I am a beginner here, I'll take a stab at 2s and enjoy hearing where I went wrong :)

After
2g Ee6s de7s Ee5e Ef5e

2s ed5s Md3e ed4s dd8s

it looked as though (to me) Gold would have eventually tried to flip the Silver camel. But playing anything as Silver starting with 2s ed5e ee5e (and so on), while it may have kept Gold from a quick flip, would allow Gold to begin advancing C+H+something in the east, knowing that the Silver elephant was going to be tied up in stalling a camel being flipped.

So, it looked like Gold had two avenues of attack, and if I either try to keep a horse hostage (as Silver) and/or deal with one attack threat to the exclusion of the other during 2s, I'm eventually left with trying to defend everything with just an elephant. My thought was:

2s ed5s Md3e ed4s dd8s

knowing that it'll take Gold a full turn to flip my camel, if that's the main goal, and still not having moved the horse hostage a single step. If the camel flip was just a ruse, with the aim of advancing C+H+something, now Gold has to burn moves going around my elephant to get back west.

I figured the best thing to do for Silver would have been overloading the west, knowing that a camel flip, retreating his horse, and attacking the west were too many options to do all at once for Gold. The one benefit for Silver now would be enough time to push his western pieces down to create some space, and keep Gold from advancing on that half of the board.

Okay, I've thought as much as I could on this, I guess it's time for me to get schooled by all of you now :)

Title: Re: A possible tactic to deal with a Horse hostage
Post by Fritzlein on Sep 22^nd, 2012, 7:22pm

Aww, you wrote the answer in plain text :'( But I guess anyone who has read this far down the thread without trying to solve it themselves doesn't deserve the joy of a puzzle anyway, so no harm done.

on 09/22/12 at 08:56:01, blackczajk wrote:

But playing anything as Silver starting with 2s ed5e ee5e (and so on), while it may have kept Gold from a quick flip, would allow Gold to begin advancing C+H+something in the east, knowing that the Silver elephant was going to be tied up in stalling a camel being flipped.

My strategic intuition is that the Gold swarm you fear isn't going to happen. Indeed, if Silver's move 2s is as chessandgo suggested above, Silver is immediately threatening a horse capture that almost forces a rabbit pull in reply. Furthermore, beyond the immediate tactics, the gold elephant on g5 is not well placed for a swarm, because it doesn't defend the f6-trap and it is in the way of anything advancing up the g-file.

Quote:

2s ed5s Md3e ed4s dd8s
knowing that it'll take Gold a full turn to flip my camel, if that's the main goal, and still not having moved the horse hostage a single step.

But if Gold flips the camel hostage (after your move) the horse hostage has become free without taking a step, and Silver is clearly in worse shape. It will be the gold elephant tied down (to defense of f3) while the silver camel becomes the strongest free piece.

Quote:

Okay, I've thought as much as I could on this, I guess it's time for me to get schooled by all of you now :)

Lecture is over; class dismissed!

Title: Re: A possible tactic to deal with a Horse hostage
Post by Boo on Sep 23^rd, 2012, 6:42am

Quote:

is

2g Ee6s de7s Ee5e Ef5e
2s ed5e ee5e cf7w dd8s
3g mg6w Eg5n Eg6s rg7s
3s mf6n mf7e rg6w mg7s

really better than the starting position for Gold?

I think it is better as gold has managed to challenge mg6 with Eg5 and at the moment Hh6 is not threatened to be captured, so gold has purchased few steps to regroup. The big question is what is the best way to search for counterplay for gold? Most possibly it is to give some kind of work for the strongest idle piece...
Where should gold move Md3? Towards hh5 or towards hb6? Probably moving towards hb6 is too risky as M without E support can become a second weakness itself.

Maybe this is the way:

1g 1g Ra1 Rb1 Rc1 Dg3 De2 Rf1 Rg1 Rh1 Ra2 Hb3 Cc2 Md3 Ee6 Cf2 Hh6 Rh2
1s 1s ra7 hb6 cc7 ed5 mg6 cf7 hh5 rh7 ra8 rb8 rc8 dd8 de7 rf8 rg7 rh8
2g Ee6s de7s Ee5e Ef5e
2s ed5e ee5e cf7w dd8s
3g mg6w Eg5n Eg6s rg7s
3s mf6n mf7e rg6w mg7s
4g hh5s Eg5e rh7w Hh6n (hh4 is closer to h3, Hh6 runs away)
4s rg7w mg6n mg7s Hh7w (silver doesnt allow Hh7 to run for the corner)
5g Md3e Me3e Dg3n Mf3e (Gold tries to counter-hostage hh4 with Mg3).

Has silver made some progress if compared to the starting position? It looks like this is going to be a horse trade.

Title: Re: A possible tactic to deal with a Horse hostage
Post by chessandgo on Sep 23^rd, 2012, 12:13pm

Maybe something like 5s rh8s mg6e Hg7s ef5e might make it difficult for Gold to avoid losing material, I'm not sure. If the rabbit on f6 is detrimental to silver's tactics, playing rg7w on 2s instead of the last dog step might be better.

Regardless of tactics, I'm going to argue that Gold's plan in your variation is not specific to clyring's tactic. With the Elephant on f5 instead of e6 in the starting position, gold can push into g6 and toy with Horses in the same fashion. If the idea is to attack silver's horse with Gold's caMel (which I believe is the correct idea in general), then 2g M->g4 should achieve a similar result, tying up EMH for emh.

Title: Re: A possible tactic to deal with a Horse hostage
Post by blackczajk on Sep 23^rd, 2012, 5:12pm

on 09/22/12 at 19:22:32, Fritzlein wrote:

Aww, you wrote the answer in plain text :'(

Oops, I guess my intent was too plainly visible . . . and a bit inaccurate, on top of it :o It's disguised now, at least for future generations. The cat is out of the bag, but I tried as best I could to put the correct animal back in the cat's place.

I couldn't quite follow what chessandgo meant at first, but I thought that it meant *if* what I had mentioned was going to happen, there wouldn't have been enough material for Silver to keep the hostage . . . and then I looked a little more closely at the board, AND your warning about the Gold caMel. It makes sense now, thank you.