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Subject: Question for Ed about Bishop pair.

Author: Eelco de Groot

Date: 13:39:38 11/04/03


Hello Ed, in case you are wandering by here in this forum, I had a "little"
question about Rebel's parameters? I was looking at the Ruffian - Rebel game
again and was wondering why actually Rebel wanted to play the move 11...Bf5.

[D]r1bqk2r/2p1bppp/p2p4/1p1P4/1n1PR3/5N2/PPP2PPP/RNBQ2K1 b kq - 0 1

Not that 11...Bf5 is an obviously bad move but as Jeroen Noomen pointed out
11...0-0 would have been better. Now my reasoning was that, if I increased the
value for the Bishop pair, maybe I'd see that the score for 11...Bf5 would go
down, since White can exchange Bishops after 11...Bf5 12.Re2 Nxd5 13.Bg5 O-O.

Black can choose to play 13...f6 instead but that does not seem a good move
either. If 13...f6 is the move Rebel expects to play, and that is the reason why
increasing [Bishop Pair] does not work, this does not seem good either since
this move weakens the pawn structure much and with short castling still an
option it seems that it is also bad because of King Safety? Or it should be?
Black has already compromised the pawn structure on the Queen side and with f6
so early in the game would weaken its pawns also on the King side. It just seems
almost fatal to do this on both sides especially early in the game, only to gain
a tempo or two (White's R back to e2 and B to d2). Also mobility of its own
Bishop on e7 is decreased by playing f6.

I experimented with different values for the Bishop pair but almost the only
effect I saw seemed to be that 13.Bd2 was chosen more than 13.Bg5, the opposite
of what I'd expect. The scores did not change noticeably, even with maximum
value of 500. So I was wondering if something could be broken here, almost as if
a plus changed into a minus or something?

Most Rebel versions I tried only want to play Bf5, except Thorsten's settings
which I don't know and also one Betazoid version where I put in [Bishop Mobility
= 60]. Another possibility I thought of that it could have something to do with
that new parameter, that is if really something might be broken?

These were the different results:

[Event "23rd DOCC"]
[Site "Leiden NED"]
[Date "25/10/2003"]
[Round "07"]
[White "Ruffian"]
[Black "Rebel"]
[Result "1-0"]
[Opening "C88 Ruy Lopez: Closed"]

1. Nf3 Nc6 2. e4 e5 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. Bd5
Nxd5 9. exd5
Nb4 10. d4 e4 11. Rxe4 Bf5 12. Re2 Nxd5 13. Bg5 O-O 14. Bxe7 Nxe7 15. Nc3 b4 16.
Ne4 Nd5
17. a3 Bg4 18. Re1 Re8 19. Qd3 Bf5 20. Nfd2 Nb6 21. Qf3 Bg6 22. axb4 d5 23. Nc5
Rxe1+
24. Rxe1 Bxc2 25. Qe2 Qd6 26. Nxa6 f6 27. b5 Bf5 28. Nf1 Bd7 29. Ne3 Re8 30. Qc2
Nc4 31. b3
Nxe3 32. Rxe3 Ra8 33. g3 Ra7 34. Qe2 f5 35. Kg2 h6 36. Nc5 f4 37. Re7 Bxb5 38.
Qe6+ Qxe6
39. Nxe6 Kh8 40. Rxc7 Ra3 41. Nxf4 Rxb3 42. Nxd5 Rd3 43. Nc3 Bd7 44. Rxd7 Rxc3
45. h4
Kg8 46. f3 Rc2+ 47. Kh3 h5 48. g4 Kh7 49. gxh5 Kh6 50. Kg4 Rg2+ 51. Kf5 Kxh5 52.
d5 Rd2
53. Rd8 Kxh4 54. d6 1-0


After 11.Rxe4, diagram see above

r1bqk2r/2p1bppp/p2p4/1p1P4/1n1PR3/5N2/PPP2PPP/RNBQ2K1 b kq - 0 1

Tg3b3 with [Bishop Pair = 500]

00:00:02.8	-0,75	1	4	O-O
00:00:02.9	-0,15	1	12	Nxd5
00:00:02.9	-0,31	2	166	Nxd5 Qe2
00:00:02.9	-0,31	2	431	Bf5
00:00:02.9	0,10	2	531	Bf5 Re2 Nxd5
00:00:03.1	0,10	3	892	Bf5 Re2 Nxd5
00:00:03.2	-0,05	4	2865	Bf5 Re2 Nxd5 Ng5
00:00:03.3	0,00	4	7238	Nxd5 Ng5 O-O Qh5
00:00:03.7	0,02	5	18689	Nxd5 Ng5 Nf6 Qf3 O-O
00:00:03.7	0,02	5	20944	Bf5
00:00:03.7	0,18	5	21625	Bf5 Re2 Nxd5 Nc3 Nxc3 bxc3
00:00:04.0	0,21	6	33068	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8
00:00:04.9	0,21	7	84244	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8 Qxc4
00:00:06.7	0,21	8	210420	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8 Qxc4
00:00:12.4	0,23	9	681436	Bf5 Re2 Nxd5 Qe1 Be6 Nc3 Nxc3 Qxc3 O-O Bf4
00:00:25.1	0,41	10	1823275	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Nxc3 Bxc3 Bf6 Ba5
00:00:49.9	0,40	11	4317423	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Nf6 a4 b4 Na2 c5
00:01:55.5	0,39	12	10731482	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Nb4 Ne1 Re8
00:05:08.5	0,37	13	29566029	Bf5 Re2 Nxd5 Bd2
00:13:28.1	0,36	14	91594057	Bf5 Re2 Nxd5 Bg5 O-O Bxe7
(Move: Bf5  (1/28)  depth=15)

Betazoid Tg3b2 with [Bishop Pair = 300]

00:00:01.8	-0,75	1	4	O-O
00:00:01.9	-0,15	1	12	Nxd5
00:00:01.9	-0,31	2	166	Nxd5 Qe2
00:00:01.9	-0,31	2	431	Bf5
00:00:01.9	0,10	2	531	Bf5 Re2 Nxd5
00:00:02.1	0,10	3	892	Bf5 Re2 Nxd5
00:00:02.2	-0,05	4	2865	Bf5 Re2 Nxd5 Ng5
00:00:02.2	0,00	4	7238	Nxd5 Ng5 O-O Qh5
00:00:02.4	0,02	5	18687	Nxd5 Ng5 Nf6 Qf3 O-O
00:00:02.4	0,02	5	20925	Bf5
00:00:02.5	0,18	5	21666	Bf5 Re2 Nxd5 Nc3 Nxc3 bxc3
00:00:02.8	0,21	6	33077	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8
00:00:03.2	0,21	7	84260	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8 Qxc4
00:00:04.2	0,21	8	209791	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8 Qxc4
00:00:07.3	0,23	9	680435	Bf5 Re2 Nxd5 Qe1 Be6 Nc3 Nxc3 Qxc3 O-O Bf4
00:00:14.7	0,41	10	1873558	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Nxc3 Bxc3 Bf6 Ba5
00:00:28.3	0,40	11	4355651	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Nf6 a4 b4 Na2 c5
00:01:04.0	0,39	12	11027147	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Nb4 Ne1 Re8
00:02:49.0	0,35	13	30278902	Bf5 Re2 Nxd5 Bg5 O-O Bxe7 Nxe7 Nc3 Re8 Qd2 b4 Ne4
Bxe4
00:07:48.2	0,36	14	86059358	Bf5 Re2 Nxd5 Bg5
00:29:40.2	0,37	15	327255945	Bf5 Re2 Nxd5 Bg5 f6 Bd2 O-O
(Move: Bf5  (1/28)  depth=16)

Tg3b met [Bishop Pair = 150]

00:00:03.3	-0,79	1	4	O-O
00:00:03.4	-0,19	1	12	Nxd5
00:00:03.4	-0,35	2	166	Nxd5 Qe2
00:00:03.4	-0,35	2	431	Bf5
00:00:03.5	0,05	2	531	Bf5 Re2 Nxd5
00:00:03.6	0,05	3	892	Bf5 Re2 Nxd5
00:00:03.7	-0,09	4	2867	Bf5 Re2 Nxd5 Ng5
00:00:03.8	-0,04	4	7435	Nxd5 Ng5 O-O Qh5
00:00:04.1	-0,01	5	18542	Nxd5 Ng5 Nf6 Qf3 O-O
00:00:04.1	-0,01	5	20795	Bf5
00:00:04.1	0,14	5	21477	Bf5 Re2 Nxd5 Nc3 Nxc3 bxc3
00:00:04.4	0,16	6	32741	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8
00:00:05.4	0,16	7	86566	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8 Qxc4
00:00:07.2	0,16	8	230398	Bf5 Re2 Nxd5 c4 bxc4 Qa4+ Kf8 Qxc4
00:00:13.0	0,22	9	709303	Bf5 Re2 Nxd5 Qe1 Bg4 Bg5 Bxf3 gxf3
00:00:23.5	0,39	10	1742090	Bf5 Re2 Nxd5 Bg5 O-O Bxe7 Nxe7 a4 Bg4 Qd3
00:00:45.1	0,33	11	3915687	Bf5 Re2 Nxd5 Bd2 Bg4 Re1 O-O Nc3
00:01:41.5	0,33	12	9748349	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Be6
00:04:52.9	0,36	13	28715021	Bf5 Re2 Nxd5 Bd2 O-O Nc3 Be6
00:14:31.7	0,33	14	86225488	Bf5 Re2 Nxd5 Qd2 O-O Nc3 Nxc3
00:52:02.5	0,35	15	306228426	Bf5 Re2 Nxd5 Bg5 O-O



[Personality = Betazoid Tg3b3] * testing Bishop Pair parameter, normally 100
[Pawn Value = 100]
[Knight Value = 101]
[Bishop Value = 100]
[Rook Value = 101]
[Queen Value = 98]
[King Safety = 150]
[Mobility = 120]
[Pawn Structure = 105]
[Passed Pawns = 105]
[Passed Pawn King Tropism = 130]
[Traditional Isolated Pawns = 80]
[Progressive Isolated Pawns = 125]
[Pins = 100]
[Bishop Pair = 500]
[Chess Knowledge = 200]
[Attractiveness = 135]
[Attacking = 130]
[Strength of Play = 100]
[Draw Contempt Factor = 0.00]
[Selective Search = 130]
[Search Technique = NULLMOVE]
[Pruning = MISC_01] * TREE: if (reduce & rd=0) goto tr76
[Pruning ? MISC_25]
[Pruning = MISC_37]
[Pruning ? MISC_40]
[Pruning = MISC_22]             * Somewhat more safe Selective Search
[Pruning = MISC_09]
[Pruning = MISC_10]
[Pruning = MISC09_2.00]
[Pruning = MISC10_4.00]
[Pruning = MISC_12]
[Pruning = SEX_HIST_DEPTH_9] * 4
[Pruning = MISC_03]             * Move ordering (safe) (speedup 4%)
[Pruning = MISC_46]
[Pruning = M46_HASH_ON]
[Adjusted Selectivity MIDG = 4] * Maximum selective depth (midgame)
[Adjusted Selectivity END0 = 4] * Maximum selective depth (early endgame)
[Adjusted Selectivity END1 = 4] * Maximum selective depth (endgame)
[Adjusted Selectivity END2 = 3] * Maximum selective depth (simple endgame)
[ANTI-GM = OFF]
[EVALUATION = NORMAL]
[Extensions (remaining)= 3]
[Extensions (checks)= 0]
[Extensions (captures)= 0]






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Last modified: Thu, 15 Apr 21 08:11:13 -0700

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