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        Arimaa >> General Discussion >> preference: EMH or ehh
        
(Message started by: ginrunner on Feb 13^th, 2012, 11:40pm)

Title: preference: EMH or ehh
Post by ginrunner on Feb 13^th, 2012, 11:40pm

I have been having a debate in my head on who has the advantage in a EMH v ehh. On the single side the EMH would be considered the stronger attack and has the ability to gain offensive control but on the other hand it leaves the m on the opposite side as the strongest free piece if silver, in this case, get an upperhand/control of the gold camel creating an elephant deadlock. At the moment I personally prefer to be the ehh in this scenario but I have been noticing many players above my skill level advancing with the EMH leading me to believe I may be missing something.

Thoughts? Which do you prefer and why?

Title: Re: preference: EMH or ehh
Post by Adanac on Feb 14^th, 2012, 7:29am

on 02/13/12 at 23:40:18, ginrunner wrote:

If the EHM attack is on the east wing, for example, it often happens that the defending silver elephant can stand on g4, with the defending horses on g6 and h5, and that wall is nearly impenetrable. If the gold pieces, especially the gold elephant, get committed to the east side then it's relatively easy for the silver camel to dominate in the west. Personally, I feel that if the EHM player tries a direct attack then the ehh defender can hold the position and silver will gain the advantage thanks to the free camel.

More and more often lately, players are trying to semi-blockade the silver elephant so that the gold camel can be activated elsewhere. I think this is the most promising strategy (until someone proves otherwise) against the ehh, which is extremely difficult to break with a traditional head-on attack. Here's a couple of games from this year's World Championship:

Hanzack tries it on move 9g here which forces the silver elephant to vacate g4.
http://arimaa.com/arimaa/games/jsShowGame.cgi?gid=209729&s=w

Hanzack completely blockades my elephant on move 7s:
http://arimaa.com/arimaa/games/jsShowGame.cgi?gid=214072&s=w

I tried a similar strategy against Fritzlein in the last round, but a slightly different situation. Because there was only 1 defending silver horse on the west wing, the silver elephant had to stand on b5 rather than b4 (to prevent Ec5w Eb5e hb6s Ha6e). This means that a semi-blockade can occur at b4 instead of c4, which I believe is more effective. However, because the silver forces were balanced, it's possible for the silver camel to transfer to c6 without leaving the east side weakened (hence the pros & cons of balanced versus unbalanced forces).

I threatened to create the blockade at 13g but Fritz moved his elephant south on 13s to prevent it:
http://arimaa.com/arimaa/games/jsShowGame.cgi?gid=215118&s=w

I'm very curious as to how these balanced vs. unbalanced games will unfold. There are lots of ideas that haven't been explored yet and opening systems could change a lot in the future if one side develops a theoretical advantage. As to which side I prefer, I change my mind quite often ;)

Title: Re: preference: EMH or ehh
Post by Fritzlein on Feb 14^th, 2012, 9:30am

Adanac summarizes nicely. The most important thing is to understand the general outline (i.e. that the EHH player has a free camel), but that's not enough. The EMH player has resources. It is finely balanced as to who has the overall advantage. It depends on the exact timing and the position of other pieces. Discovery of what seems like a small point can entirely tip the balance of power and change Adanac's mind again.

I will happily play either side of this face-off. There is much subtlety and much to learn. I figure if I understand it better than my opponent, I can gain an advantage by making better moves, regardless of who has the better alignment to begin with.

Title: Re: preference: EMH or ehh
Post by ginrunner on Feb 14^th, 2012, 10:08am

That makes a lot of sense. I may prefer the EHH because I have MUCH more experience on that side of the equation than I do on the EMH side (attributable to my setup).

The dynamics of the EMH attack are still fuzzy to me. I had never really considered the elephant blockade to be a strength of the attack because typically when people try it they send too much strength over and I can easily start a winning race with camel and dogs on the opposite side. Looking at the Hanzack games I can see he doesn't allow for this possibility so my strategy of allowing the blockade to happen would easily lose the game.

Another thing I want to note is if each side trades a horse (I am thinking of my most recent game with Adanac here) who is better off in a positional sense? In that game (granted I was outplayed, I accept that ;)) I thought I had a great position (at the time) because my EH and his EM were both completely trapped together leaving my camel on the other side, but I didn't have enough power to capitalize on it. This was one of the reasons I didn't mind the fatal swarm that ensued as I saw it just building on something I thought would help me long term (He moves his elephant away I can clean up pieces that are readily available).

Title: Re: preference: EMH or ehh
Post by Fritzlein on Feb 14^th, 2012, 11:26am

on 02/14/12 at 10:08:13, ginrunner wrote:

Another thing I want to note is if each side trades a horse (I am thinking of my most recent game with Adanac here) who is better off in a positional sense?

If you have M facing h and H facing m, is it symmetrical, right? Any positional advantage would have to come from some *other* feature of the position.

Title: Re: preference: EMH or ehh
Post by tharkun on Feb 15^th, 2012, 7:48am

Mmm, I basically had no real idea of what you all were talking about until I played a game with this specific imbalance.

on 02/14/12 at 07:29:44, Adanac wrote:

If the gold pieces, especially the gold elephant, get committed to the east side then it's relatively easy for the silver camel to dominate in the west. Personally, I feel that if the EHM player tries a direct attack then the ehh defender can hold the position and silver will gain the advantage thanks to the free camel.

Exactly this happened in ginrunner's game against me yesterday (http://arimaa.com/arimaa/games/jsShowGame.cgi?gid=215680&s=w). I was outplayed in the opening phase and his camel was free to dominate the other wing, until he unneccessarily allowed counterplay.