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Subject: Re: ECM - first 100 problems summary

Author: Amir Ban

Date: 01:34:15 02/03/98

Go up one level in this thread



In response to the Don & Bruce posts, here's my summary based on my
notes and other posted opinions.

Just to define an important term: I call a line vague if a strong player
would not necessarily choose to play it even if he sees it. This applies
to 28 (which is arguably correct), but not to 29, which has 3 solutions
but is not vague. When vagueness doesn't apply I would add side
solutions.

** 11 Nxg4   Amir : no change
** 14 Nd5    Amir : add Nb5 (Nd5 Nb5)
** 16 Rxc5   Amir : You may find this, but it's based on faulty line
(drop)
** 17 Rxd5   Amir : add Nf6 (Rxd5 Nf6)
** 19 Rxf6+  Amir : change to Nxe6 (Nxe6)
** 28 Rxf4   Amir : vague or faulty (drop)
** 29 Rgxg6  Amir : add Rxa6 and Rf4 (Rgxg6 Rxa6 Rf4)
** 43 Bxg2+  Amir : add Qxc2 (Bxg2+ Qxc2)
** 51 Bxh2   Amir : vague (drop)
** 60 Bxh2+  Amir : Qh6 is right (Qh6)
** 63 Ncxd5  Amir : Nbxd5 is equivalent (Ncxd5 Nbxd5)
** 68 Bd3    Amir : wrong (drop)
** 71 Qh6    Amir : Kg2 is stronger. Some may argue to leave Qh6 on
(Kg2)
** 76 fxg6   Amir : add fxe5 (fxg6 fxe6)
** 81 Qb1+   Amir : Bxc6 is the same trick in a different way (Qb1+
Bxc6)
** 82 exf6   Amir : Was never disputed on CCC. No change
** 84 Bg6    Amir : vague (drop)
** 91 Nc6    Amir : vague (drop)
** 96 Qe8+   Amir : Some versions don't have Nf6+ as solution (Qe8+
Nf6+)

Amir


On February 02, 1998 at 13:19:49, Bruce Moreland wrote:

>
>On February 01, 1998 at 18:20:48, Don Dailey wrote:
>
>>Hi People,
>>
>>I  have gone through all  the posts on the ECM  test set for the first
>>100  problems.  Basically we  are trying only  to correct the problems
>>and discover side  solutions or cooks.  We are  throwing out a few and
>>changing a few.  If I missed someones post  please forgive me but this
>>is not an easy task.  A lot of your comments were weak, ambigious etc,
>>so I had to take some guesses.
>
>Yes.  This is not a very good place to do this work, since it isn't
>convenient to download all of the pertinent stuff.  I'm going to risk
>being redundant by commenting on some of these, since it's so hard to go
>back and figure out what others have said.
>
>>DELETE
>>
>>  14 - most thought it very vague
>>  19 - seems to have at least 3 solutions, vague
>>  28 - consensous on vagueness
>>  63 - conflicting. Positonal and changing solutions.
>>  68 - Amir and Bob both want dropped.
>>  82 - vague problem.
>>  84 - vague
>>  91 - too many solutions
>
>14) Nd5 (the key) wins the exchange for a pawn.  Mine finds this
>initially in a few seconds, with a score of +0.3 or so.  Other stuff
>gets in the way but after an hour and twelve minutes mine sticks with
>this for good at around +0.6, ending up at +0.73 after four hours.
>
>19) There is more than one way to win big in this position.
>
>28) Mine lines Nf6+ gxf6 Rxf4 after an hour, at -0.51.  This one stll
>might be correct, since Rxf4 is the key, but I haven't let it go for
>longer.
>
>63) Ncxd5 (the key) is +2.6 after 20 seconds, but I haven't run it
>longer.
>
>68) Don't know, only ran it for an hour.
>
>82) I get exf6 (the key) in 38 seconds +3.36, which replaced the
>previous move, Qg3, which had been at +2.56.  I let it go for four
>hours.  The last PV I got was at two hours and eighteen minutes, and was
>+6.46.  So if this was vague, it's also crushing.
>
>84) Mine finds Bxg6 (the key) in about a minute and a half, at +2.19,
>and still has it after an hour at +2.30.  Other moves might also win, I
>don't know.
>
>91) I think there is more than one way to win big here, too.
>
>>CHANGE
>>
>>  11 - Change key to (Nxg4)
>>  17 - Add Nf6+ as a solution (Rxd5 Nf6+)
>>  60 - Change solution to (Qh6)
>>  81 - Add Bxc6 as side solution
>
>I think that, in general, if someone wants to add a new move, they
>should either get a really big score or run for a really long time and
>end up with a score that is still obviously winning.  In some of these
>cases, mine gets the proposed new move initially, then switches.
>
>11) The key is already Nxg4.
>
>17) No opinion.
>
>60) No opinion.  Mine also selects Qh6.
>
>81) The key seems to get you into a B vs N ending with an extra outside
>passer.  I assume that the proposed new move wins a pawn but leaves more
>material on.  Unless it also leads to a position a strong player (not
>us) would like as much, I wouldn't like to add it as a new solution to
>anything, since it wouldn't be as good as the original key.  But on the
>other hand, this isn't a positional test, so perhaps it would be best to
>remove it from any test sets that are derived from ECM.  This one is
>easy, anyway, you'll get either Qb1+ or Bxc6 in a very short time.
>
>>There are still 4 problems in the first 100  that I cannot resolve.  I
>>would like 1 more  pass at these with more  committal decisions.  If I
>>get  no more comments  I  will just  drop them.
>>
>>
>>29 Rgxg6       ; Amir wants Rxa6 as side solution.
>>29 Rgxg6       ; Bob thinks Rgxg6 might be best move despite Amirs side.
>>29 Rgxg6       ; Ernst thinks Rf4 might be best.
>>29 Rgxg6       ; Don says Cilkchess likes Rf4 with score jump
>
>I think Rf4 might end up better, too, but I only ran it for 3 minutes.
>
>>43 Bxg2+       ; Amir wants Qxc2 as side solution.
>>43 Bxg2+       ; Bob gets solid Bxg2+ and sticks. Amir thinks there is a
>>side.
>>43 Bxg2+       ; Don says cc2 oscillates between Qxc2 and Bxg2 for an
>>hour
>
>No opinion.
>
>>51 Rxh2        ; Amir isn't sure it's correct
>>51 Rxh2        ; Bob and Amir are both not sure.
>>51 Rxh2        ; Don thinks Qc5 might be worth looking at.
>>51 Rxh2        ; Ernst get's fail high with Rxh2 thinks best.
>>51 Rxh2        ; Don says CC2 likes Qc5 after 1 hour
>
>I still have Qxc5 after an hour, but I think Ernst's line should get
>people looking at Rxh2 for longer, possibly.
>
>>
>>76 fxg6        ; Amir wants fxe6 as side solution.
>>76 fxg6        ; Bob seems to believe fxg6 is clearly better than Amirs
>>side.
>>76 fxg6        ; Ernst agree's to side solution of fxe6
>>76 fxg6        ; Don says fxe6 played by CC2 after 1 hour but fxg6 is
>>close.
>
>fxg6 and fxe6 are both > +5 in a very short time.
>
>bruce



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