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Subject: Howard's positional sacrifice test

Author: Ed Schröder

Date: 10:09:37 12/01/99


I ran Howard's test, Rebel Century had no problems with all 9 positions. I
will comment the interesting ones and paste the crucial lines of the LOG.

r1bb2k1/p1q2pp1/4p1np/2ppP2Q/8/2P2N2/2P2PPP/R1B1R1K1 w - - am Bxh6;
00:00:14  9.00  0.33   1.c4 d4 2.Bd2 a5 3.Ra3 a4 4.Rea1 Bd7 5.Rb1

r3q1k1/ppp1rpp1/2n1b2p/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - - bm f4h6;
00:00:00  1.00  1.02   1.Bxh6 gxh6 2.Qxh6
00:00:00  4.04  0.88   1.Bxh6 gxh6 2.Qxh6 f5 3.Bxf5 Bxc4  4.Bg6

The position which started the whole issue.
----------------

r3q1k1/ppp1rpp1/4b1np/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - - am BXH6;
00:00:16  8.00  0.26   1.Bg3 Rd8 2.Qb4 b6 3.Bxg6 fxg6 4.Bh4 g5 5.Bg3 Bf7

3rrnk1/ppp1qpp1/4b2p/8/2P2B2/3B4/PPPQ1RPP/5RK1 w - - id BXH6spe;
00:00:14  8.00  0.48   1.Qa5 c6 2.Qxa7 Ra8 3.Qd4 c5 4.Qc3 Rxa2 5.Bg3

3r1rk1/p2q1ppp/2pb1n2/5b2/1nB5/2N1BN1P/PP2QPP1/R4RK1 b - - bm BXH3;
00:00:52  9.00  0.31   1..Rfe8 2.Nd4 Bxh3 3.gxh3 Qxh3 4.Nf3 Qg4+
00:02:19  9.19  0.41   1..Bxh3 2.gxh3 Qxh3 3.Rac1 Ng4 4.Ne4 Nxe3 5.Qxe3 Qg4+
6.Ng3 Bf4

Rebel Century needs SEARCH + EVAL to find the find the sac.
-----------

3r1rk1/p2q1ppp/2pb4/p4b2/1nB5/4BN1P/PP2QPP1/R4RK1 b - - am BXH3;
00:00:54  9.00  0.82   1..Rfe8 2.Rfd1 Nc2 3.Ng5 Re7 4.Rac1 Nxe3

1qr1b1k1/4bpp1/pn2p2p/1p1nN3/3P4/P2BBN1Q/1P3PPP/4R1K1 w - - bm Bxh6;
00:00:00  3.01  0.20   1.Bxh6 gxh6 2.Qxh6 Nf6 3.Ng5 a5
00:00:00  4.00  0.23   1.Bxh6 gxh6 2.Qxh6 Nf6 3.Ng5 Qd6 4.Bh7+ Nxh7 5.Qxh7+ Kf8
6.Nexf7
00:00:00  5.00  0.30   1.Bxh6 gxh6 2.Qxh6 Nf6
00:00:05  6.00  1.30   1.Bxh6 Nf6 2.Bg5 Qd6 3.Bxf6 Bxf6 4.Qh7+ Kf8 5.Qh8+ Ke7
00:00:08  7.00  1.39   1.Bxh6 Nf6 2.Bg5 Nbd5 3.Nd2 Bd6 4.b4
00:00:21  8.00  1.39   1.Bxh6 Nf6 2.Bf4 Qb7 3.Ng4 Nbd5  4.Nxf6+ Nxf6 5.Ne5+
00:00:49  9.00  1.42   1.Bxh6 Nf6 2.Bg5 Nbd5 3.Bxf6 Bxf6 4.Qh7+ Kf8 5.Qh8 Ke7
6.Ng4

Another working case of an early positional sacrifice. SEARCH proves Rebel
is right.
---------------

1qr1b1k1/4bpp1/p3p2p/1p1nN3/3P4/P3BN1Q/1P3PPP/4R1K1 w - - am Bxh6;
00:00:00  1.01  0.13   1.Bxh6 gxh6 2.Qxh6
00:00:00  2.00  -0.34   1.Bxh6 gxh6 2.Qxh6 f6 3.Ng6
00:00:00  3.00  -1.02   1.Bxh6 gxh6 2.Qxh6 Bf8 3.Qh5 Bg7
00:00:00  3.01  -0.39   1.Qg3 Nxe3 2.fxe3 Rc2
00:00:00  4.00  -0.40   1.Qg3 Nxe3 2.fxe3 Rc2 3.b4
00:00:00  4.02  -0.34   1.Bd2 Rc2 2.Qg4 Nf6 3.Qg3 Bd6
00:00:00  5.00  -0.28   1.Bd2 Rc2 2.Qg3 g5 3.b4
00:00:01  6.00  -0.34   1.Bd2 Bd6 2.Qg4 Nf6 3.Qg3 Rc2
00:00:03  7.00  -0.34   1.Bd2 Rc2 2.Qg4 Kf8 3.b4 Bd6
00:00:09  8.00  -0.40   1.Bd2 Rc2 2.Qg4 Kh8 3.Qh5 Rxb2 4.Nxf7+
00:00:37  9.00  -0.34   1.Bd2 Rc2 2.Qg4 Kh8 3.b4 Qc7
00:02:17 10.00  -0.38   1.Bd2 Rc2 2.Qg4 Kf8 3.b4 Qc7

This is a very interesting one. The first 2 plies Rebel Century sacs the bishop
but then is corrected by SEARCH after seeing 2..Bf8 and 3..Bg7 on the third
ply. Isn't CC sometimes wonderful?
-------------------

r1br2k1/p1q2pp1/4p1np/2ppP2Q/2n5/2PB1N2/2P2PPP/R1B1R1K1 w - - bm Bxh6;
00:00:17  8.08  0.00   1.Bxh6 gxh6 2.Qxh6 Rd7 3.Bxg6
00:01:43  9.00  0.62   1.Bxh6 a5 2.Bg5 Re8 3.Bxg6 fxg6 4.Qxg6 Rf8

Thanks Howard for interesting set. If you have more please post.

Ed




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