BB+P vs RN

Traditional chess games and chess topics in general

Moderators: hgm, Rebel, chrisw

User avatar
Nordlandia
Posts: 2822
Joined: Fri Sep 25, 2015 9:38 pm
Location: Sortland, Norway

BB+P vs RN

Post by Nordlandia »

Can black draw with optimal play in this imbalance that arise from the game Berthelot vs Glenn Flear [1988]
8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

5k2/ppp2ppp/1b6/8/6b1/2P5/PP4PP/RN2K3 w - - 0 20

"An unbalanced position has arisen straight out of the opening, in which, with an open centre, Black has a pawn and the bishop pair for the exchange. Is it enough compensation?"
Glenn Flear wrote:
The defender probably has more chances of successfully defending with the pair of bish-
ops than "with other minor piece combinations. This seems to hold true even when the board
isn’t opened up for bishops. Indeed, there is a certain school of thought that claims that ’a
pair of bishops equals a rook and knight in the ending’. I’m not sure that this assertion can be
proven, but I decided to look at it from a statistical point of view.

From a sample of 68 high-level games in the NQE of rook and knight vs two bishops (this
time with players rated 2550 and above), there were 30 wins for the rook< and knight duo, 20
for the bishop pair, and 18 draws.

The number of wins achieved by the bishops seems quite high, which may reflect the
double-edged nature of this imbalance, but the overall percentage is a respectable 57% to
43%. We can interpret this as such: a pair of bishops shouldn't be underestimated, but the
rook and knight are still superior.
G. Kasparov wrote:
Indeed, two bishops and a pawn are often sufficient compensation for a rook and knight.
When the side down the Exchange has the bishop pair, my data shows he needs only 1.15 pawns to make things even.
Dann Corbit
Posts: 12777
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: BB+P vs RN

Post by Dann Corbit »

The game:
[Event "7"]
[Site "Pau"]
[Date "1988.??.??"]
[EventDate "1988.??.??"]
[Round "?"]
[Result "1/2-1/2"]
[White "Yannick Berthelot"]
[Black "Glenn Flear"]
[ECO "C30"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "101"]

1. e4 e5 2. f4 Bc5 3. Nf3 d6 4. c3 Nf6 5. fxe5 dxe5 6. Nxe5
O-O 7. d4 Bb6 8. Bg5 Qe8 9. Qf3 Nbd7 10. Nxd7 Nxe4 11. Nxf8
Nxg5+ 12. Qe2 Bg4 13. Qe5 Qxe5+ 14. dxe5 Re8 15. Bd3 Rxe5+
16. Kd2 Ne4+ 17. Bxe4 Rxe4 18. Re1 Rxe1 19. Kxe1 Kxf8 20. Nd2
c6 21. Nb3 Be6 22. Kd2 Bd5 23. g3 g6 24. Re1 f5 25. Nc1 h5
26. a4 h4 27. Nd3 hxg3 28. hxg3 a5 29. b4 axb4 30. cxb4 Bc7
31. Nf4 Bd6 32. Nxd5 cxd5 33. Re6 Bxb4+ 34. Ke2 Bc5 35. Rxg6
Kf7 36. Rh6 b6 37. Rc6 Ke7 38. a5 Kd7 39. Rf6 bxa5 40. Rxf5
Ke6 41. Rf1 a4 42. Kd3 a3 43. Kc2 Ke5 44. g4 Ke4 45. g5 d4
46. g6 d3+ 47. Kb3 Bd4 48. Kxa3 d2 49. Kb3 Kd3 50. Rh1 Be5
51. Rd1 1/2-1/2
User avatar
Nordlandia
Posts: 2822
Joined: Fri Sep 25, 2015 9:38 pm
Location: Sortland, Norway

Re: BB+P vs RN

Post by Nordlandia »

Can Komodo 9.3 manage to draw this endgame against latest stockfish dev?
Dann Corbit
Posts: 12777
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: BB+P vs RN

Post by Dann Corbit »

In the actual game that was played the game was easily won for white if he had played Kf3 instead of a5 at move 38.

8 
7 
6 
5 
4 
3 
2 
1 
abcdefgh

8/4k3/1pR5/2bp1p2/P7/6P1/4K3/8 w - - acd 34; acs 37; bm Kf3; c3 "a5"; ce 576; pm Kf3; pv Kf3 d4 Ke2 d3+ Kxd3 Bf2 Ke2 Bd4 Kf3 Bg1 Kf4 Bf2 Rg6 Bd4 Rg5 Kf6 Rxf5+ Kg6 Rd5 Bg1 Rd6+ Kf7 Kf5 Bc5 Rf6+ Ke7 Rc6 Bf2 Kf4 Bg1 Ke4 Bf2 Kf3 Bd4 Rc4 Bg1 Rf4 Ke6 g4 Kd5 Rf5+ Kd4;

Analyzed game positions:
https://www.dropbox.com/s/oh9h93jjtmhez ... ge.7z?dl=0
User avatar
Nordlandia
Posts: 2822
Joined: Fri Sep 25, 2015 9:38 pm
Location: Sortland, Norway

Re: BB+P vs RN

Post by Nordlandia »

LENOVO-PC-2, Rapid 10m+10s 2015


1 Komodo 9.3 64-bit +35 ½1½½010½½10½½½½1½½½1 11.0/20
2 Stockfish 031215 64 POPCNT -35 ½0½½101½½01½½½½0½½½0 9.0/20

55% score for K9.3.
User avatar
Nordlandia
Posts: 2822
Joined: Fri Sep 25, 2015 9:38 pm
Location: Sortland, Norway

Re: BB+P vs RN

Post by Nordlandia »

K9.3 won over Stockfish 031215 64 POPCNT in 20 games à la 10+10 TC.

55% score is very close to Glenn Flear suggested 57% (superiority from a statistical point of view).













Dann Corbit
Posts: 12777
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: BB+P vs RN

Post by Dann Corbit »

Nordlandia wrote:LENOVO-PC-2, Rapid 10m+10s 2015


1 Komodo 9.3 64-bit +35 ½1½½010½½10½½½½1½½½1 11.0/20
2 Stockfish 031215 64 POPCNT -35 ½0½½101½½01½½½½0½½½0 9.0/20

55% score for K9.3.
Komodo is stringer and it is only 20 games. What is this supposed to tell us?
Dann Corbit
Posts: 12777
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: BB+P vs RN

Post by Dann Corbit »

With this game count and K being stronger, there is no conclusion of any sort that can be drawn from this.
User avatar
Nordlandia
Posts: 2822
Joined: Fri Sep 25, 2015 9:38 pm
Location: Sortland, Norway

Re: BB+P vs RN

Post by Nordlandia »

Dann Corbit wrote:With this game count and K being stronger, there is no conclusion of any sort that can be drawn from this.
Of course there can be drawn some conclusions.

Since black never won a single game, black was always worse.

So the conclusion is that the RN side is the favourite side Ceteris Paribus, (hinted by Gleen Flear).
Dann Corbit
Posts: 12777
Joined: Wed Mar 08, 2006 8:57 pm
Location: Redmond, WA USA

Re: BB+P vs RN

Post by Dann Corbit »

Nordlandia wrote:
Dann Corbit wrote:With this game count and K being stronger, there is no conclusion of any sort that can be drawn from this.
Of course there can be drawn some conclusions.

Since black never won a single game, black was always worse.

So the conclusion is that the RN side is the favourite side Ceteris Paribus, (hinted by Gleen Flear).
I think the conclusion may be valid, and the test does offer some evidence, but I think a clear test would be like this:
1. Use the same engine for both sides
2. Run 2000 games at least.

Then we will probably know the answer (unless it is too close to decide)
Taking ideas is not a vice, it is a virtue. We have another word for this. It is called learning.
But sharing ideas is an even greater virtue. We have another word for this. It is called teaching.