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Subject: Re: Positional/Real Sacrifice

Author: Ed Schröder

Date: 00:35:54 11/30/99

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>Posted by Robert Hyatt on November 29, 1999 at 20:17:47:

[ snip ]

r3q1k1/ppp1rpp1/2n1b2p/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - - bm Bxh6;

>>>>00:00:00  1.00  1.02   1.Bxh6 gxh6 2.Qxh6
>>>
>>>
>>>
>>>This looks _incredibly_ dangerous.  For every position where Bxh6 works,
>>>there are 10 positions where Bxh6 loses.  Here a piece for two pawns looks
>>>awful if the other pieces can't get over to help out...  Speculative play is
>>>nice, as in the old days of the Novag gadgets from Kittinger, and in the
>>>current
>>>play of CSTal...  but it can backfire big-time as well...
>
>>>
>>>Crafty doesn't like the sac, unless it sees actual material coming back,
>>>because
>>>I have spent a lot of time teaching it which types of material imbalance are
>>>bad and which types are good.  A piece for 2 pawns is always bad unless
>there
>>>is some tactical conclusion at the end.  And given the above PV there
>>>obviously
>>>isn't anything except a somewhat naked king position for black...
>>
>>I can not believe you saying this. After 1.Bxh6 gxh6 2.Qxh6 there is a queen,
>>2 rooks and a bishop all pointed very dangerous at a naked king. Rebel giving
>>+1 is fully justified.
>>
>>Every 1800 rated chess player will play 1.Bxh6 immediately, no need to
>>calculate.
>>
>
>Sorry, but _I_ am an 1800+ player and _I_ wouldn't play it immediately.
>Because black can play f5, and it doesn't look nearly so clear after that.  The king
>has a way out...  the black rook now can interpose on the g/h files.  The
>f file is no longer useful unless white does something else...

1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5 the black king is even more naked. I guess
we have a different view on king safety.

>It may be good.  It may not work.  But as a human, I don't play Bxh6 here
>without calculating something worthwhile at the end of the sequence.  I let
>an IM look at this for several minutes...  he left unclear whether it was
>good or not...

Who was the IM?

After 1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5 I am pretty sure all programs soon will
display a +2 or +3 score.

Based on this I wouldn't call this position a 100% positional sacrifice as
it is somewhere in the 10th ply area (depending on a programs extension
use).

>That is what I meant by "this looks incredibly dangerous".  Because if you
>don't get something back from this, you are pretty well sunk.  The position looks
>pretty nice for white.  But good enough to toss a piece immediately?  Unclear
>without a lot more analysis...
>
>to me

As said we must have a different view on king safety even on the basics as
this case for me is so crystal clear: QRRB all pointed at a naked king, the
king having hardly any escapes, the black pieces not able to defend its
own king. Based on that Rebel gives a 2 pawn positional bonus after
2.Qxh6 and even more after 3.Bxf5.

See also my points regarding this issue in another posting.

Ed





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