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Arimaa >> General Discussion >> eH hostage? Mh hostage position?
(Message started by: Gerenuk on Mar 11th, 2008, 10:01pm)

Title: eH hostage? Mh hostage position?
Post by Gerenuk on Mar 11th, 2008, 10:01pm
I was wondering where to put the E if he does a e-H-hostage?
I read Ed6, but on c5 I could immediately pull his horse, if his e choses to leave and he replaces hb6?!

What to do after a e-H hostage (by him)? On the other wing M-m seems equal. I thought my E can still hop between d6 and c5 juggling piece to my c3 trap. Chessandgo does this standard move and I wonder why people miss that.
If my E is not doing anything, then effectively EH+e are inactive and he has an advantage. So I conclude I need to use my E? How?
Or how do I flood the e-H pack? I thought I need to flood d6, but can't see how to do this reliably.

How do I hostage his horse with my camel? I watched games and people seem to retreat H when m arrives. Can E not disrupt m so that H doesn't have to worry?

Title: Re: eH hostage? Mh hostage position?
Post by Fritzlein on Mar 12th, 2008, 9:20am

on 03/11/08 at 22:01:43, Gerenuk wrote:
I was wondering where to put the E if he does a e-H-hostage?
I read Ed6, but on c5 I could immediately pull his horse, if his e choses to leave and he replaces hb6?!

If his b6-elephant has your horse hostage on a6, the main reason to keep your elephant on d6 rather than c5 is to make it more difficult for his camel to cross over.  He doesn't want to leave with his elephant and put a horse on b6, he wants to leave with his elephant and put a camel on b6.


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What to do after a e-H hostage (by him)? On the other wing M-m seems equal.

No, the camels on the other wing are not quite equal.  Your camel can go to g6 and still be far from his elephant and therefore safe, because your elephant on d6 interposes.  His camel can't go to g3 without being in danger from your elephant switching wings and winning a camel for the hostage horse you abandon.


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I thought my E can still hop between d6 and c5 juggling piece to my c3 trap. Chessandgo does this standard move and I wonder why people miss that.

Most people don't study other people's games, which means they learn more slowly than you.  :)


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If my E is not doing anything, then effectively EH+e are inactive and he has an advantage. So I conclude I need to use my E? How?
Or how do I flood the e-H pack? I thought I need to flood d6, but can't see how to do this reliably.

You already mentioned one way to use your elephant, namely flipping a small piece or rabbit towards your side.  This is a very effective (albeit slow) way to beat Bomb when he takes your horse hostage.  For swarming, it is best to start up the a-file, not the c-file.  Often Bomb will not realize the danger, and will let its elephant be smothered.  Humans, though, will get their elephant out in time, which leaves a more subtle situation in determining whose elephant is more free to leave.

Piece-flipping and swarming were the original ways discovered to defeat Bomb holding a horse hostage with an elephant, but a third idea is also effective against Bomb and more fun against humans, namely attacking the other trap with MH.  There is a lot of exploration yet to be done in such positions, and the last word on the E holding H hostage has not yet been written.


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How do I hostage his horse with my camel? I watched games and people seem to retreat H when m arrives. Can E not disrupt m so that H doesn't have to worry?

Usually your elephant can prevent his camel from crossing, although not if you put your elephant on c5 like you suggested before.  Sometimes his camel can get across on the seventh rank even if you leave your elephant on d6 to be in the way.  The main obstacles are his rabbits, such as rabbit on c7 like I often have, or a rabbit on d8 like Omar often has, which you can pull to d7.  To get his camel across on the seventh rank, your opponent will put his camel on e7, leaving d7 open, with a cat or dog on both d8 and c7, and a piece in f6 to unfreeze his camel if you pull it to e6.

Usually the opposing camel can eventually get across on the eighth rank in spite of an interposed elephant, but this is far too slow a plan if your camel is active on the opposite wing in the mean time.  I don't even consider doing a back-rank camel crossing except to harass an opposing horse on c7, and then only if I have to get around my rabbit on d7 which is in the way.

If the situation were so simple as "the defending camel can never get across" or "the defending camel can always get across", the theory of the EH attack would be much easier than it actually is, and we might have figured out exactly how to do it by now.

Title: Re: eH hostage? Mh hostage position?
Post by Gerenuk on Mar 12th, 2008, 12:01pm

on 03/12/08 at 09:20:02, Fritzlein wrote:
Most people don't study other people's games, which means they learn more slowly than you.  :)

Actually all I learned is from the bot ladder (yet to be completed). I have a list of 100 tricks now :) Just sometimes I like missing single-move H losses.
When watching high class games it looks to me like random pulls that are undone easily until someone does a mistake. I wonder if its not possible to rather improve the position (i.e. setting up a solid 3rd row, displace his rabbits) and then pull some minor pieces.


on 03/12/08 at 09:20:02, Fritzlein wrote:
For swarming, it is best to start up the a-file, not the c-file. Often Bomb will not realize the danger, and will let its elephant be smothered.

My main concern is how to swarm the trap without losing pieces there. It seems I need to fill the trap c6, have a piece on c5 and - harder - keep a piece in d6?!


on 03/12/08 at 09:20:02, Fritzlein wrote:
If the situation were so simple as "the defending camel can never get across" or "the defending camel can always get across", the theory of the EH attack would be much easier than it actually is, and we might have figured out exactly how to do it by now.

Provided the camel manages to cross. What would be a favourable M-h hostage position?

In fact for E-m hostage, is anything else apart from (Eb3, ma3, Ra1, Ra2, Cb2) recommended?

Title: Re: eH hostage? Mh hostage position?
Post by Fritzlein on Mar 13th, 2008, 9:49pm

on 03/12/08 at 12:01:04, Gerenuk wrote:
My main concern is how to swarm the trap without losing pieces there. It seems I need to fill the trap c6, have a piece on c5 and - harder - keep a piece in d6?!

The long-term objective is for your elephant to be able to leave d6.  You will want to replace it with a piece as strong as possible, ideally your camel, but a horse may have to suffice depending on the circumstances.  Yes, before you rotate out of d6, you will want to occupy c6 and c5.

My point about starting on the a-file is an attempt to smother the hostage-holding elephant before you try to fill in the trap.  An aware opponent always has the option of rotating his elephant to c5, perhaps re-occupying b6 with his own horse while pushing your c5-piece towards the center, and framing the piece you have been so kind to put into c6 for him.  If you occupy b5 before you occupy c6 and c5, your opponent will not have enough steps for this rotation.  Furthermore, if you occupy a5 and a4 before you occupy b5, your opponent can be in a pickle.  His elephant is threatened with smother, but if he rotates his elephant out immediately he doesn't get anything for it (no frame, no piece he can push into the middle) and your pieces on the a-file will protect your camel to dive towards b6 and dislodge his horse so your horse can take b6.

Against Bomb, starting by occupying a5 and a4 usually means you will get an elephant blockade out of it, which makes it much easier for your elephant to leave d6 later on.


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Provided the camel manages to cross. What would be a favourable M-h hostage position?

You don't want your camel to be your furthest-forward piece, or it might get taken hostage itself by the elephant that was defending.  Nice is ha3 Mb3 Ha4 Ra2 Ra1 Rb2 Cc2.  Nicer is hb2 Mb3 Ha4 Ra3 Ra2 Rb1 Cc2.  Nicest is hc1 Mc2 with smaller pieces in the vicinity to keep the camel safe from an invading elephant.

Generally speaking if you have a camel holding horse hostage, the value is that it lets your elephant roam while his elephant is stuck defending.  However, the opposing elephant that is "defending" will then temporarily be the locally strongest piece.  Eventually it will be able to turn the defense into an attack of some sort.  The value of the hostage is therefore measured in how long it will take the opposing elephant to turn the tables, or at least get his horse to freedom.


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In fact for E-m hostage, is anything else apart from (Eb3, ma3, Ra1, Ra2, Cb2) recommended?

That's the best.  The important thing then is the position of your own horses and camel relative to his horses.  You need piece activity, or your elephant can get smothered on b3, just as when it is holding a horse hostage.  It's more difficult for the opposing elephant to rotated out of defense when you have a camel hostage than when you have a horse hostage, but it still can be done to you if you just wait passively.

I have seen a "high hostage" work with Ec4 mb4 Hb5 Ra4 Ra3.  That's not the way you would want to set it up, but it can result from catching the opposing camel in the act of trying to get your horse hostage.



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