Welcome, Guest. Please Login or Register.
Aug 22nd, 2019, 9:31pm

Home Home Help Help Search Search Members Members Login Login Register Register
Arimaa Forum « Move 18 »


   Arimaa Forum
   Team Games
   2007 One vs TheMob
(Moderators: supersamu, RonWeasley)
   Move 18
« Previous topic | Next topic »
Pages: 1 2  Reply Reply Notify of replies Notify of replies Send Topic Send Topic Print Print
   Author  Topic: Move 18  (Read 1852 times)
Fritzlein
Forum Guru
*****



Arimaa player #706

   
Email

Gender: male
Posts: 5928
Move 18
« on: Nov 28th, 2007, 9:49pm »
Quote Quote Modify Modify

18w is a move where chessandgo's most direct choices don't seem to help him that much, so we can expect something more subtle and positional.  The odds are in favor of him not choosing one of the three moves in the tree.  Still, here they are for what it is worth:
 
17b hb5e md5s Dc4w md4w
.    18w Ed6s hc5n Ed5w Db4w
.    .    18b mc4w Da4n mb4w hc6w
.    .    .    19w Ec5w Eb5s ma4s Eb4w
.    .    .    .    19b hb6w ha6e Da5n dd7s
.    .    .    .    .    20w Ea4n Da6n Ea5s Rb1n
.    .    .    .    .    .    20b hb6n hb7s Da7e ra8s
.    .    .    .    .    .    .    21w Hb3n Hb4n Ea4e Eb4s
.    .    .    .    .    .    .    .    21b hb6w Db7s Db6e Dc6x ha6e (=+)
.    .    .    19w Ec5s Ec4w Eb4n ma4e
.    .    .    .    19b hg6e hh6w Rh5n dd7s (=+)
.    18w Ed6s Ed5n hc5e Db4w
.    .    18b mc4n hd5s hd4w rb8s
.    .    .    19w Ed6s Ed5n mc5e Da4s
.    .    .    .    19b hc4e md5w hd4w rb7s (=+)
.    .    18b mc4w Hb3w mb4s rc8e
.    .    .    19w hd5s Ed6s Ed5w Ec5s  
.    .    .    .    19b mb3n rc3w rb3s hd4n
.    .    .    .    .    20w Ec4n mb4e Ha3e Da4e
.    .    .    .    .    .    20b dd7s hd5s Db4n mc4w (?)
.    .    .    .    .    20w Da4n Ha3e mb4w Ec4w
.    .    .    .    .    .    20b hd5w hc5w dd7s dd6s (?)
.    .    .    .    19b mb3s rc3w Cc2n mb2e
.    .    .    .    .    20w rb3n Cc3w Cb3s Ha3e (+=)  
.    18w Ed6s Ed5s hc5e Db4w
.    .    18b dd7s hd5w mc4w hc5w (=+)

IP Logged

Soter
Forum Guru
*****



Arimaa player #2381

   
Email

Gender: male
Posts: 138
Re: Move 18
« Reply #1 on: Dec 5th, 2007, 3:42pm »
Quote Quote Modify Modify

Jean's decision: Ra2e Ed6s Db4w Da4s
IP Logged
Fritzlein
Forum Guru
*****



Arimaa player #706

   
Email

Gender: male
Posts: 5928
Re: Move 18
« Reply #2 on: Dec 5th, 2007, 4:12pm »
Quote Quote Modify Modify

Surprise!  Now we have no tree.  My first thought: 18b hc5w hb5w ha5s mc4w.
IP Logged

mdk
Forum Guru
*****



Arimaa player #2309

   


Gender: male
Posts: 108
Re: Move 18
« Reply #3 on: Dec 5th, 2007, 5:58pm »
Quote Quote Modify Modify

on Dec 5th, 2007, 4:12pm, Fritzlein wrote:
Surprise!  Now we have no tree.  My first thought: 18b hc5w hb5w ha5s mc4w.

 
This move was my first thought as well and I don't see any forcing response for gold or any better move for us. I think there may be a chance that we can gain some significant reserve time on this move
IP Logged
Fritzlein
Forum Guru
*****



Arimaa player #706

   
Email

Gender: male
Posts: 5928
Re: Move 18
« Reply #4 on: Dec 5th, 2007, 6:38pm »
Quote Quote Modify Modify

Now that computers are explicitly allowed, I had to check...  Bomb's first inclination is 18b mc4w mb4n Hb3n rc3w.  Actually that is Bomb's only inclination so far, from 4-step search up to 11-step search.  Bomb has chosen a move and is sticking with it, evaluating the position as essentially even.
 
I think this move is strategically poor.  After chessandgo replies 19w Ed5s Ed4w rb3e Hb4s, we are worse off than at present.  We can't charge with our camel since our horse is not in front protecting it, and we can't get our horse out in front because the camel is in the way.  We have lost time in our general objective of getting the gold elephant so distracted in the west that we can take his rabbit for free in the east.
 
Of course, Bomb thinks its move is gaining ground by getting the silver camel to safety.  It is a move worth considering if attacking moves seem to get our camel in unacceptable trouble.  For the moment, however, I think Bomb is just short-sighted, and not able to see that a camel advance by us won't necessarily give up the camel hostage, but could eventually buy us time for our g6-horse to capture the h5-rabbit in f6.
 
I'll let Bomb run overnight to give it a chance to change its mind, but I already suspect Bomb is going to be useless in the near term.  It's just going to want to retreat our camel, since that's all the strategy its pea brain can hold.
IP Logged

RonWeasley
Forum Moderator
Forum Guru
*****




Harry's friend (Arimaa player #441)

   


Gender: male
Posts: 882
Re: Move 18
« Reply #5 on: Dec 5th, 2007, 8:10pm »
Quote Quote Modify Modify

If he responds 19w Ed5s Ed4w mb5n Ec4w, do we pull the h5 rabbit or do we run our own rabbits up the a and b files?
IP Logged
Fritzlein
Forum Guru
*****



Arimaa player #706

   
Email

Gender: male
Posts: 5928
Re: Move 18
« Reply #6 on: Dec 5th, 2007, 9:18pm »
Quote Quote Modify Modify

on Dec 5th, 2007, 8:10pm, RonWeasley wrote:
If he responds 19w Ed5s Ed4w mb5n Ec4w, do we pull the h5 rabbit or do we run our own rabbits up the a and b files?

I was thinking we should try to capture his h-rabbit at that point.  In the few lines I played out, it can get tricky if he defends f6 with his horse, since our camel and elephant are both occupied, but it seems that we have a slight edge in the ensuing mess.
IP Logged

arimaa_master
Forum Guru
*****



Arimaa player #2010

   


Gender: male
Posts: 358
Re: Move 18
« Reply #7 on: Dec 6th, 2007, 7:09am »
Quote Quote Modify Modify

Just to throw out my first inclination:
 
18b cc7s dd7w hc5w ce7w
 
 
But I admit that suggested: 18b hc5w hb5w ha5s mc4w
 
seems to be better.
 
 
IP Logged
Fritzlein
Forum Guru
*****



Arimaa player #706

   
Email

Gender: male
Posts: 5928
Re: Move 18
« Reply #8 on: Dec 6th, 2007, 8:38am »
Quote Quote Modify Modify

on Dec 5th, 2007, 6:38pm, Fritzlein wrote:
I'll let Bomb run overnight to give it a chance to change its mind, but I already suspect Bomb is going to be useless in the near term.  It's just going to want to retreat our camel, since that's all the strategy its pea brain can hold.

Well, I was right about the final outcome.  At 16 steps search depth Bomb wants to play 18b hc5w mc4n mc5n rg7e, running away with our camel  for no gain.  That's all the deeper Bomb searched in 12 hours; with no capturing lines to guide it, Bomb can't prune as aggressively.
 
Bomb temporarily favored 18b hc5w mc4n mc5n hb5n at 15 steps depth, running away even more determinedly, and at 14 steps depth Bomb preferred 18b hc5w hg6e hh6w rg7e, which wastes two steps!  But buried next to this trash was a legitimately interesting move Bomb liked at 12 & 13 steps depth:
 
18b hc5w hg6e hh6w Rh5n
 
At first I thought this was easily refuted by 19w Ed5w mc4e Ec5s De2n, but after playing a few lines I'm not so sure.  Sometimes it seems to just end in a rabbit trade, but sometimes it seems we can capture the h5-rabbit without giving up our framed one.
 
In any case, I still prefer 18b hc5w hb5w ha5s mc4w, which seems to achieve the same goal of letting us go after h5-rabbit next turn, but with more options for us and fewer options for chessandgo.  Incidentally, when I fed my preferred move to Bomb, it considered it -0.99 for us, i.e. putting us behind by a rabbit positionally, which is bunk.  I think I've had my fun with Bomb for this move, and will make more progress with my unaided brain for the present.  
« Last Edit: Dec 6th, 2007, 8:39am by Fritzlein » IP Logged

RonWeasley
Forum Moderator
Forum Guru
*****




Harry's friend (Arimaa player #441)

   


Gender: male
Posts: 882
Re: Move 18
« Reply #9 on: Dec 6th, 2007, 9:23am »
Quote Quote Modify Modify

Do we like 18b hc5w hb5w ha5s mc4w enough to approve it with a voice vote?  So far all commenting mobsters like this move with no competing alternatives.
IP Logged
Fritzlein
Forum Guru
*****



Arimaa player #706

   
Email

Gender: male
Posts: 5928
Re: Move 18
« Reply #10 on: Dec 6th, 2007, 11:08am »
Quote Quote Modify Modify

on Dec 6th, 2007, 9:23am, RonWeasley wrote:
Do we like 18b hc5w hb5w ha5s mc4w enough to approve it with a voice vote?  So far all commenting mobsters like this move with no competing alternatives.

Strategic summary: Each side has an exposed rabbit, his on h5 and ours framed on c3.  We are menacing c3 so that chessandgo's elephant is forced to defend it.  We hope to thereby gain time to capture the h5 rabbit while our c3 rabbit remains merely framed.  Chessandgo has a variety of objectives.  If he can take our camel hostage, it may be worth it for him to give up his h5-rabbit in exchange.  If he can drive our camel over to the east, then our horse alone may not be enough of a threat to c3 to tie his elephant to defense.  Given enough time, his elephant can threaten something in f3, which could force our elephant to abandon the c3 rabbit.  Also chessandgo can complicate by advancing his g3-horse.
 
We could conceivably be forced to abandon our c3-rabbit without capturing his h5-rabbit.  Alternatively the race could end in a tie, with both sides having to give up their respective rabbits, in which case who is ahead or behind will be determined by other features of the resulting position.  I believe, however, that we are somewhat ahead in this race, and therefore we should not be happy with a tie.  Chessandgo will probably look for an opportunity to give up his rabbit for a threat that makes us abandon our rabbit, and he will be happy if he achieves that.
 
My main line currently looks like this:
 
18b hc5w hb5w ha5s mc4w
.    19w Ed5w Ec5w mb4e Eb5s
.    .    19b mc4n hg6e hh6w Rh5n
 
I am also concerned about the "strategic" move 19w Ed5w Ec5s Hg3n Hg4n, which doesn't directly threaten anything, but is calculated just to frustrate us.
« Last Edit: Dec 6th, 2007, 11:08am by Fritzlein » IP Logged

99of9
Forum Guru
*****




Gnobby's creator (player #314)

  toby_hudson  


Gender: male
Posts: 1412
Re: Move 18
« Reply #11 on: Dec 6th, 2007, 3:52pm »
Quote Quote Modify Modify

What about a rabbit pull right now?
Something like
hg6e hh6w Rh5n hc5w
or
hg6e hh6w Rh5n mc4w
 
(I've only looked at the position for a few seconds, so do let me know the refutation if you've already found it.)
IP Logged
UruramTururam
Forum Guru
*****




Arimaa player #2537

   
WWW

Gender: male
Posts: 319
Re: Move 18
« Reply #12 on: Dec 6th, 2007, 5:03pm »
Quote Quote Modify Modify

Fine! I like when we have to start from scratch!
 
My first thought: 18b  hg6e hh6w Rh5n dd7s
 
Similar move to the ones proposed by 99of9 but with a different last step...
IP Logged

Caffa et bucella per attactionem corporum venit ad stomachum meum.
BGG Arimaa badges - get your own one!
arimaa_master
Forum Guru
*****



Arimaa player #2010

   


Gender: male
Posts: 358
Re: Move 18
« Reply #13 on: Dec 7th, 2007, 3:54am »
Quote Quote Modify Modify

on Dec 6th, 2007, 3:52pm, 99of9 wrote:
What about a rabbit pull right now?
Something like
hg6e hh6w Rh5n hc5w
or
hg6e hh6w Rh5n mc4w
 
(I've only looked at the position for a few seconds, so do let me know the refutation if you've already found it.)

 
 
That move ( 18b hc5w hg6e hh6w Rh5n) was mention by Fritzlein (this was bomb's suggestion at depth 12 and 13).
 
And explanation followed (see 3rd post above yours).
 
« Last Edit: Dec 7th, 2007, 3:54am by arimaa_master » IP Logged
RonWeasley
Forum Moderator
Forum Guru
*****




Harry's friend (Arimaa player #441)

   


Gender: male
Posts: 882
Re: Move 18
« Reply #14 on: Dec 7th, 2007, 6:53am »
Quote Quote Modify Modify

I couldn't find any obvious problem with doing the rabbit pull now.  However, I like doing it after the proposed hc5w hb5w ha5s mc4w because this separates our west side pieces from the h5 rabbit by an extra square and puts our camel-horse right on gold's horse-dog.  This makes our west threat better and the rabbit capture harder to defend.
 
Let's expect a vote Monday morning.
IP Logged
Pages: 1 2  Reply Reply Notify of replies Notify of replies Send Topic Send Topic Print Print

« Previous topic | Next topic »

Arimaa Forum » Powered by YaBB 1 Gold - SP 1.3.1!
YaBB © 2000-2003. All Rights Reserved.