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Subject: Re: ECM errata (301 thru 400)

Author: Amir Ban

Date: 04:19:05 01/29/98

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On January 28, 1998 at 13:45:07, Howard Exner wrote:

>Posted by Amir Ban on January 27, 1998 at 11:53:23: *
>

>
>*No. 336 (Rxd4):
>
>*I find Bxe5! as a free gain of a pawn. I don't know what the point of
>*Rxd4 is.
>
>*Recommend: Change key to Bxe5.
>
>#335
>Book: 1...  Rxd4 2.Rxd4 Be5 3.Rd8 f5 4.Kh3 Rxf2 5.Rd3 Kh5 0-1
>To avoid this line I think white will have to drop all the pawns
>which is also hopeless. Is there a defense for white? The mate theme
>is pretty.
>

This one's 335 of course. In the line above black mustn't play 5.Rd3 but
let the f-pawn go. Is the win of R+B+3P vs R+R easy ? Should compare it
to the position after 1...Bxe5 2.Rxe5 Rxd4+ 3.Kf3. I evaluate the two
positions about the same. Which of these is actually won ?



>*No. 354 (Qxf3):
>
>*This one's unclear. 1...Qxf3 2.Nxf3 Rxh3+ 3.Kg1 Rxf3 is a nice position
>*for black but I don't see a decisive line. This may be meant as a
>*positional sacrifice. It doesn't look inferior to any other
>possibility,
>*which may be a basis for accepting it.
>
>*Recommend: Investigate.
>
>Book continues with 3 white replys: Nc4, Qd1 and Qh2 which all fail.
>Rebel 8 suggests Qb4 with the following position:
>5rk1/2p3pp/p1p5/2P1p3/1Q1pPn2/1P3r2/PN6/R5K1 b - - id "Pos 354 -
>ECM.EPD"
>Now here black should avoid a draw sequence and play h5! which
>gives his king some breathing room so that the rook on f8 can
>be lifted. So for now it looks ok to play Qxf3 but programs may
>play this to draw initially.
>

I got as far as Qb4 h5 but remained unconvinced. I have a positive score
here, but I don't see a forced win and it's not clear how long black can
maintain the threats and contain the white pieces. If he can't he may
lose.


>*No. 366 (Rxd8):
>
>*I think this one's wrong. 1.Rxd8 Qxd8 2.Qh4 Kg8 3.Rxf6 white gets two
>*minor pieces for a rook, but will be sorry he did after 3...Qb6 which
>*gives black a strong counterattack.
>
>*Recommend: Discard.
>
>The book only considers Bc4 instead of Kg8.
>As white I would continue your above line with 4.h6! Qxb2(what else?)
>5.Rh6! f6 6.Rxh7 1-0 but there might be some better play for black
>after h6. If this holds then Rxd8 is good.
>

I suppose you mean 4.h3?

Then try 4...Rc6. All continuations are unclear: 5.Rh6 gxh6 6.Bf6 Qe3 or
5.Nd1 Rxc2 or 5.Qg3 Kf8 or 5.Bh6 gxh6.


>
>*No. 367 (Rd5):
>
>*I have no clue here. A black rook is en prise and Junior just takes it
>*Bxf8 for a score of 266. Anything wrong with that ? Instead Rd5 places
>a
>*white rook en prise for no obvious purpose.
>
>*Recommend: Discard.
>
>The book move is the pretty Nxd5!
>

You mean Nd5. This move's correct but my version of ECM says Rd5. So
this is a typo.

Conclusion: Key move is Nd5.


>*No. 371 (Rxd5):
>
>*I think this is based on faulty defense: 1.Rxd5 cxd5 2.c6 Bc8 3.Ba6 Ka8
>*and black is not in trouble.
>
>*Recommend: Discard.
>
>This is a long Nolot kind of position unless there is a flaw in the
>following book
>line: 1.Rxd5 cxd5 2.c6 Bc8 3.Ba6 Ka8 4.Nd4!! Qg4+ 5. Kb1 Qe3 6.Bb7+ Kb8
>7. Rd1 Be7 8.Qb5 1-0.  Be7 is poor but I can't see a defense at this
>point. Is there
>a better defense earlier on though?
>

How about 5...Qg4 ?




>*No. 381 (e5):
>
>*I choose fxe6 (Bxe6 Nd4 or fxe6 e5) which evaluates about the same as
>*e5. Both options are not decisive in my opinion.
>
>*Recommend: Discard.
>
>Book: 1.e5 dxe5 2.Ne4 Qb6 3.Nd6+ Ke7 4.Nxe5! fxe5 5.f6! bxf6
>6. Rxf6 and according to the book white will mate or win big material.
>If this is all forced then e5 looks stronger than fxe6.
>

This works well with the black queen on b6, but if 2...Qc6 the same
continuation doesn't work well. Black can play Rcf8 (best) or even Kxf6.


Amir



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