Shakmaty Bereolos - The Official Chess Site of Peter Bereolos

8/31/18 - Friedman-Bereolos, 2002 Kings Island Open

The ending of my game against David Friedman at the 2002 Kings Island Open is another B vs. N battle, this time I was on the attacking side with the knight. The most interesting parts of this game remained under the surface. After 58...Nxf4

my intuition in 2002 was correct that if Black could reach a position with his knight on d4 and king on c4, he would be winning. However, the tablebase shows that this cannot be forced. 59.Bf5 Nd5 60.Be6 Ne3+ 61.Kc1! 61.Kb1 c2+! 62.Kb2 Kd3! 63.Kc1 Kc3 followed by Nf1-d2-b3+ 61...Kd3 62.Bd7 Nc4 63.Bb5 Kd4

64.Bd7 Ne5 65.Bf5 Nc6

66.Bd7 Nb4 67.Bf5 Nd5 68.Bd7 Ne3 69.Bc8 Kc4 70.Bd7 c2 A variation to show that Black can get his knight to d4, but not with his king on c4 is 70...Nf1 71.Be6+ Kb4 72.Bf5 Nd2 73.Bg6 Nf3 74.Kc2! Nd4+ (74...Kc4 75.Bf7+) 75.Kd3! 71.Be6+? Also bad is 71.Kd2? but Black must play very accurately to bring home the point. 71...Kb3! 72.Kc1 Ng2! 73.Bf5 Ne1! 74.Kd2 Nf3+! (74...Kb2? 75.Bxc2! Nxc2 76.Kd3 and White will exchange the last pawn) 75.Kc1 Nd4 76.Bxc2+ other bishop moves are met by 76...Kc3 and the white bishop can't cover both e2 and b3 76...Nxc2! 77.Kd2 Nd4 (77...Kb4 is actually shorter, but who would play such a move?) 78.Kd3 Ne6! 79.Ke4 Ng7! 80.Kd5 {80.Kf4 Kc4 81.g5 Ne6+! (81...f5? 82.Ke5 Kd3 83.g6! [83.Kf6? gives away a crucial tempo 83...f4! and Black queens] 83...Ke3 84.Kf6! f4 85.Kxg7! and both sides queen) 82.Kf5 fxg5!} 80...Kc3 81.Kd6 Kd4 82.Ke7 Ke5 -+ The route to the draw was as I had analyzed in 2002: 71.Kb2 Kd3 72.Kc1! Kc3 (here 72...Ng2 is met by 73.Bf5+ picking up the c-pawn) 73.Ba4!

Black can't effectively lose a move to reach this position with White to play, when it would be zugzwang. 71...Kc3 72.Bf5 Nxf5 73.gxf5 73.g5 Nd4 73...Kd3 0-1

Lessons from this ending: 1. The knight can almost never lose a tempo to a bishop. The defense with a bishop against a knight often hinges on this crucial point. The zugzwang position in the last diagram particularly illustrates this. 2. Every tempo matters. I chose the diagrams for this post very carefully. Each of these positions is winning for Black if the other player was on move. I'll leave it as an exercise to the reader to figure them out. 3. Keep the game going when you have the advantage and can play without risk. You never know when your opponent might blunder.

I was also thinking about adding the eternal Be Patient rule here, but it is tough to say in this example. When I first analyzed this game, I thought maybe 70...c2 was a mistake because I couldn't crack the position after 73. Ba4 in post game analysis. However, at the time, and in the heat of battle, it is very difficult to realize that Black doesn't have triangulation or some other means of passing the move back to White. Also, knowing that White has that defense, it is easy to suggest that knight on d4 instead of e3 might be an improvement. However, during the game it is difficult to judge the correct square for the knight. On e3 the knight attacks the pawn on g4, so it isn't clear that it wouldn't be the best square. These kinds of considerations are what makes chess such a difficult game.

8/29/18 - BCE-314a

Position 314a is a short little problem. Black appears to have set up the frontal defense in a R+P vs. R ending. However, White manages to advance his pawn tactically in nice parallel variations where the same theme of attacking the rook while threatening mate appears with the Black king on a6, a5, or a4.

8/26/18 - Hevia-Bereolos, 2018 US Masters

Last month when I posted my 2004 win against GM Arthur Bisguier I noted that I hadn't defeated a GM since that time, but was still on the hunt for more. Lightning struck in my next GM encounter last week versus Carlos Hevia in the first round of the US Masters. This was a rematch of last year's opening round, which he won in a lopsided battle. I only had the modest goal of playing a more competitive game this year. He missed a couple of tactics, but still had counterplay right up until the end of the game. This was also a milestone for me as it was the first time I defeated a GM with the Black pieces.

8/22/18 - BCE-356b

Position 356b shows the difficulties the attacker can sometimes run into in a rook ending with two connected passed pawns if they are rook and knight pawns. Fine's main line of 1...Kg7 is a simpler draw, but Black can still hold with rook moves along the a-file because of stalemate tricks. This idea can crop up even if the defender doesn't have a pawn if the attacker gets careless as Tennesee Tempo fans might painfully remember from the game Shen-Larson. It's a good reminder for the defender to look for such tries, especially if the king is already witout moves.

8/15/18 - BCE-458, Zukertort-Steinitz 1886

BCE-458 is a very interesting ending from what is generally considered the first official World Championship match between Steinitz and Zukertort. This match was played under the rules that Bobby Fischer later championed with draws not counting and the winner required to score 10 wins with a drawn match provision should the score reach 9-9. After Steinitz won the first game, Zukertort rattled off four consecutive victories. This didn't seem to bother Steinitz who proceeded to amass his needed nine further wins over only 15 games. The BCE example is the only other win scored by Zukertort but it did narrow the score to 6-5 with 2 draws.

I had some additional interest in this game because I had previously looked at it in the context of my 2008 game with Carl Boor. That game also featured a rook and two connected passed pawns versus a bishop and knight. I was able to quickly force a blockade and drew without difficulty. Fine states that it is winning for the side with the rook and pawns and If the pawns are further back, a methodical advance will get them to their goal. That was a bit suspicious to me since in the Boor game, he was not able to avoid a blockade, and in the Zukertort-Steinitz game the win was still difficult with the pawns further advanced. Therefore, I decided to dig deeper.

The first interesting discovery was that the pawns started much further back in the world championship game, so it was curious that Fine did not include this as an example of how to win with the pawns. The game entered the RPP vs BN ending after 68. Rxh4

That the tablebases already show this position to be a draw despite the poor position of Black's king is enough to overturn Fine's general conclusion. However, in a practical game the chances are with White. I'm not going to give a whole lot of description to the following moves as I don't really understand much of the tablebase defense beginning with the very first move 68...Nf5? 68...Bc5! is the only drawing move. I can't fully explain the reason for this I guess keeping the knight on d4 deprives the White king of e2 while the bishop may be helping stop the king from going to f2. But after 69. f4 one of the drawing moves is 69...Bd6, so I think I need to shrug and declare "computer move".

Speaking of computer moves, it is interesting to see how engines without tablebases evaluate the diagram position. We can get a sampling of this from the ChessBase "Let's Check" feature. When I opened that up on this position, I got the following 3 evaluations

0.91 depth=27 68...Bc5 69. g3 Kc6 Komodo 12.1.1 64-bit
1.23 depth=32 68...Bc5 69. Rh6 Bd6 Stockfish 8
1.48 depth=41 68...Bc5 69. g3 Ne6 Komodo 10.4 64-bit

Interestingly, all 3 find the move 68...Bc5! with varying degrees of evaluation of White's position (all much greater than the true 0.00). It's also notable that Komodo 10.4 goes wrong on the very next move with 69...Ne6? which is mate in 82.

After Steinitz's blunder of 68...Nf5? there is a different set of engines in Let's Check, and while the evaluation has increased in White's favor, it is still on the margin of what would be considered decisive.

1.37 depth=39 69. Rh7+ Kc6 70. g4 Komodo 12.1.1 64-bit
1.80 depth=29 69. Rh7+ Kd8 70. Ke2 Deep Fritz 14 x64
1.89 depth=29 69. Rc4+ Kd7 70. Ke2 Houdini 6.03 x64

This time it is the newer version of Komodo that gives away a half point with 70. g4? when either 70...Nd4 or 70...Ne7 is a draw. This further goes to show that although engines have gotten super strong, they are still not perfect.

69. Rh7+ Kd8 70. g4? Like the Komodo line above, this is a mistake. Deep Fritz's 70. Ke2 is the most efficient win. 70...Ne7? Unlike the position from the Komodo line, here only 70...Nd4! is good enough for the draw. 71.Kg2 Ke8 Steinitz gave 71...Ng6 72.Kf3 and Ke4, but faster is 72.Rh6 Nf4+ 73.Kf3 Be5 74.Ke4 Bg7 75.Ra6 and the Black knight is forced to move out of play while White follows up with 76. f4 72.Kf3 Bc5 73.Rh5 Bd4 74.Kg3 Kf7 75.f4 Bc3 76.Rb5 Be1+ 77.Kf3! on other moves Black plays ...Ng6 and forces the f-pawn forward after which Black can establish a dark-sqare blockade. 77...Bc3 78.g5 Ba1 79.Kg4 Bc3 80.f5 Bd4 81.Rb7 Bc3 82.Kh5

This is the BCE-458 position. The game concluded 82...Bd4 83.Kh6 Bg7+ 84.Kh7 Be5 85.g6+ Kf8 86.Rxe7 1-0

While researching this ending, I came across another World Championship example nearly 100 years later, from game 2 of the second Karpov-Kasparov match in 1985. This one only occurs in Kasparov's notes after 52.Bb4

The game concluded 52...Kf7 Kasparov gives 52...Rd4 as Black's best chance. 53.Nc3 Rb8 54.Na2 Rb5 55.g4 Rb8 56.Kd3 Rd8+ 57.Kc4 Rd1 58.Bxa3 Ra1 59.Kb3 Rh1 60.gxh5 Rxh3+ 61.Nc3 Rf3 [61...Rxh5 62.Ne4 defends the pawn because of Nd6+] 62.Bc1 Rxf5 63.h6 g6 64.Ne4 Rh5 65.Bb2 1/2-1/2

Because of the defense with Nd6+ Kasparov also analyzes 52...Kh7!? to avoid this. Then, if White defends like he did in the game, our endgame of interest is reached 53.Bc3 Rb8 54.Bb4 (Kasparov indicates the better defense 54.Nb4 Rb5 55.g4 Rb8 56.Kd3 Ra8 57.Na2 Ra4 58.Bb4 Kh6 59.Bd2+) 54...Rb5 55.g4 Rb8 56.Kd3 Rd8+ 57.Kc2 hxg4 58.hxg4 Rd4 59.Bxa3 Ra4 60.Kb3 Rxg4 61.Bc1 Rg3+ 62.Nc3 Rf3 63.Kc2 Rxf5

with the conclusion it is not easy to give a definitive evaluation of this position, but in practice...Black would have had excellent chances of success. Thanks to the tablebases we can now give the assessment Black mates in 57, but we can also see how narrow the conversion path is through the short continuation that Kasparov gives 64. Kd3 Rf3+ 65. Be3

Here he stops with two possibilites: 65...g5 and 65...Kg6. I'll leave it as an excercise to the reader to determine which move wins and which is only a draw.

8/13/18 - Bereolos-Bisguier, 1989 US Open

The other time I faced GM Bisguier was in the 1989 US Open. This was a somewhat dull game, but it was still memorable for me as it was my first draw against a GM. Regarding my comment at the end that Ulf Andersson would have played on, I give you the game Andersson-Milov from the 1997 FIDE KO tournament. 1.d4 Nf6 2.Nf3 d5 3.c4 e6 4.g3 dxc4 5.Qa4+ Nbd7 6.Bg2 a6 7.Nc3 Rb8 8.Qxc4 b5 9.Qd3 Bb7 10.0-0 c5 11.dxc5 Bxc5 12.Bf4 Rc8 13.Rad1 b4 14.Na4 Be7 15.Ne5 Bxg2 16.Kxg2 Qa5 17.Nxd7 Qxa4 18.Nxf6+ Bxf6 19.b3 Qc6+ 20.Qf3 Qxf3+ 21.Kxf3

The same material and a similar pawn structure to the variation at the end of Bereolos-Bisguier 21...Rc3+ 22.Kg2 a5 23.Rd6 g5 24.Be3 a4 25.bxa4 0-0 26.a5 Ra8 27.a6 Ra3 28.a7 Rxa2 29.Rd7 Kg7 30.Rb7 Rxe2 31.Rd1 b3 32.Rb8 1-0

8/10/18 - Raghavan-Bereolos, 2018 National Senior Tournament of Champions

My only loss in the event was to Vijay Raghavan from the host state of Wisconsin. He thoroughly outprepared me in the opening reaching a small endgame advantage through move 22, while I was on my own after only 11 moves. I finally bailed out to what should have been a drawn rook ending a pawn down. I proceeded to completely butcher it with a series of substandard moves, and found myself in a lost position after 43...Rxh4

44.Ra8+ Ke7 45.Rxa5 Rh2 46.Rg5 A small ray of hope. I expected 46.g4 h4 47.f4 which should be relatively easy for White 46...h4 47.Kg7? White still had a path to the win here with 47.f4 h3 48.g4! Rg2 49.Kf5! h2 50.Rh5 Kf7 51.g5 Kg7 52.Rh6 and White will be able to collect the h-pawn by walking his king walk back to g3 via g4 or e4 47...h3! 48.gxh3 Rxh3! 49.Re5+ Kd6! 50.f4 At this point I felt that I should be able to draw, but I did not find the correct technique 50...Rf3! 51.Rf5 Ke6 52.Kg6

52...Ke7? 52...Rg3+! 53.Rg5! Re3! preventing Re5+ 54.f5+ Ke7! 55.Kg7 (55.Rg1 Kf8) 55...Rf3! and White can't make progress He gave me no further chances 53.Rf7+! Ke6 54.f5+ Ke5 55.Re7+ Kf4 56.f6 Rg3+ 57.Kf7 Kg5 58.Re8 Rf3 to prevent Kg7 59.Rg8+ Kh6 60.Rg6+ Kh7 The king made it around to the short side, but the rook needs to be on a square like a3 in order to give checks from the side. 61.Rg2 Kh6 62.Rh2+ Kg5 63.Kg7 1-0

Lessons from this ending. 1. Don't get discouraged. There will be plenty of time after the game to kick yourself over bad moves. As long as the game is going you have to be ready if your opponent presents you with an opportunity. 2. Keep studying the endgame, there is always more to learn. I had never seen the drawing method with the king on the long side of the pawn before.

8/8/18 - BCE-365/Spielmann-Alekhine, New York 1927

Position 365 shows the power of an active king in a 2 vs. 1 rook ending with no passed pawns. This example comes from the the elite New York 1927 tournament, which was the last big showdown between Capablance and Alekhine before their World Championship match. The leadup to the BCE position is instructive as well.

The slightly odd position of the Black rook is explained by the fact that he just captured a pawn on h6. This position doesn't look like it should hold much danger to White, but watch how quickly Spielmann collapsed. 60. Ke3 Kg4 61. Re4+ In Alekhine's tournament book he suggests 61. Ke2 Rh1 62. Re4+ Kf5 3. Ra4 with equality. Black could still try 62...Kh3 as in the game, but with the Black rook on h1, White can even play 63. Rf4 f5 64. Ra4 followed by counterattack against the Black pawns after 64...Kg2 65. Ra6! g5 66. Rf6 f4 67. Rf5! Rh5 68. Ra5 and White is holding 62...Kh3 63. Rf4? Reaching the BCE-365 position. In addition to the active Black king, the White rook finds itself on an awkward square. Alekhine points out that White could still have drawn with 63. Ke2. The game didn't last much longer 63...f5! 64. Rf3+ Kh2! 64...Kg2? allows White to tie the Black rook to g6 with 65. Rg3+! 64. Rf4 Now, 64. Rg3 is met by 64...Rh3! with a winning pawn ending. 64...Rh3+ 0-1The f-pawn is falling for example 65. f3 Kg2 66. Ke2 Rh8 67. Ke3 Re7+ 68. Kd2 Kg3 or 65. Ke2 Kg2 when 66. f3 transposes to the previous note and other moves are met by 66...Rf3

The defense via perpetual check in the BCE correction should also help the reader to solve the following Black to play and draw exercise from Aagaard's Endgame Play

8/4/16 - Bereolos-Perez, 2018 National Tournament of Senior Champions

I was at the US Open site last weekend to take place in the first ever National Tournament of Senior Champions. I'm providing the following annotated game for the Tennessee state newsletter, so I thought I'd share it here as well.

I had the privilege of representing Tennessee in the inaugural National Tournament of Senior Champions. This is the 3rd invitational tournament that has been modeled after the Denker Tournament of High School Champions following the Barber Tournament of K-8 Champions and the National Girls Tournament of Champions. It was a pretty strong field with 4 grandmasters (Fishbein, Zapata, Rohde, and Sevillano). I was seeded 6th out of 42 players and ended up tied for 6-9th. My best effort was in the final round with White against the Washington state representative FM Ignacio Perez. 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.f4 0-0 6.Nf3 c5 7.d5 b5 8.cxb5 a6 9.a4

There is an interesting anecdote associated with this position. The 2017 South Carolina Senior Open served as their qualifier for this tournament for the highest scoring resident. Going into the last round, I led South Carolina's Klaus Pohl by half a point. Before the round Klaus was furiously calculating tiebreakers and then told me that if we drew then he would be guaranteed to be the SC representative, while I would take clear first in the tournament. So after playing 9. a4, I offered a draw, expecting an early trip back to Knoxville. Instead, Klaus' fighting spirit took over and he declined! I wasn't too upset by this as I have a huge score from the diagram position (+9 =1 -1) and went on to win a nice game. Things still worked out for Klaus as Daniel Quigley was unable to attend the Tournament of Champions and Klaus got to represent South Carolina after all. 9...e6 Klaus continued with 9...Qa5 10.Be2 The other main line here is 10.dxe6 which I used successfully against Justin Daniel in the 2000 Land of the Sky tournament. 10...axb5 11.Bxb5 White has lost a tempo with Be2xb5, but Black has some issues with his development as well. In particular, he needs to find a good square for Nb8. In the game, this was a problem he did not manage to overcome. 11...exd5 12.e5 dxe5 Theory considers 12...Ne8 the best way to equalize, but White won the only game I found with this in the database. 13.fxe5 Ne4 This move surprised me. I expected 13...Ng4 which allows Black to recover the e5 pawn more quickly than in the game although White still retains some pull. 14.Qxd5 Nxc3 15.Qxd8 15.Qxa8?! Qd1+ 16.Kf2 Qc2+ looked too dangerous to me, but the engine says Black doesn't have more than perpetual check. Afterwards, we also looked at the line 16...Qxh1 17.bxc3 Bg4 18.Bb2 Bxf3 19.Qxf3 Qxh2 and concluded Black was in trouble because of the passed a-pawn after 20.a5 15...Rxd8 16.bxc3 Bd7 We spent alot of time in the post mortem looking at alternatives here. We concluded 16...h6 stopping Bg5 was likely the best try, but such a non-developing move isn't going to bother White too much and he is still pressing after 17.Be3 17.Bg5 Re8 18.0-0 Bxe5 19.Nxe5 Rxe5 20.Bf6 I decided on this move because it boxed in the Black king. The other move I considered was 20.Bf4 which has the advantage of targeting Nb8. White also has a big edge here, for example 20...Re8 21.Rad1 Bxb5 22.axb5 Ra7 23.b6 Rb7 24.Bc7 and Black is quite tied up. 20...Bxb5 This loses by force. Also bad is 20...Rf5 21.Rxf5 Bxf5 22.Rd1 and Nb8 is completely dominated; Probably the best Black can do is something like 20...Re4 21.Rad1 Ra7 22.Rd6 (22.Rfe1 to trade the active rook is also good.) 22...Bxb5 23.axb5 Nd7 24.b6 Rb7 25.Bd8 and Black still has problems to solve 21.axb5 Rxa1

22.Bxe5 White should also win the rook ending after 22.Rxa1 Re6 23.Ra8 Rxf6 24.Rxb8+ Kg7 25.Rc8 but I was able to calculate the B vs. N ending all the way to a win. 22...Rxf1+ 23.Kxf1 Nd7 The knight finally leaves home, but it is much too late 24.Bc7 c4 25.b6 Nc5 26.Ke2 Nb7 26...Kf8 27.Bd6+ was the point of forcing the knight to c5. 27.Ke3 Kf8 28.Kd4 Na5 28...Ke7 29.Kxc4 Ke6 30.Kb5 Kd5 31.c4+ Kd4 32.Bg3 f5 33.c5 is no better 29.Kc5 Ke7 30.Kb5 Nb7 31.Ka6 31.Kxc4 would transpose to the note after Black's 28th move. 31...Nc5+ 32.Ka7 Ke6 33.b7 Nxb7 34.Kxb7 Kd5 35.Kb6 f5 36.Kb5 g5 37.g3 h5 38.h4 Black resigned, the ending is easily won for White, for example 38...gxh4 39.gxh4 Ke4 40.Kxc4 f4 41.Bb8 f3 42.Bg3; 38...f4 39.gxf4 gxh4 40.f5 h3 41.Bh2 h4 42.Kb4 1-0

I'd like to thank the US Chess Senior committee, especially David Grimaud, for getting this tournament off the ground. The Denker started the year after I graduated high school, so I never had the opportunity to play in that event. The tournament was smoothly run by John Haskell with no incidents. All rounds started on time and were well spaced so that you could analyze with your opponent and still get a decent meal between rounds. That's something all tournaments should strive for. Also, thanks to the ICC, which provided memberships to all participants in all 4 invitational tournaments. Finally, thanks to the TCA which provided a small travel stipend which helped offset some of my expenses. Congratulations to GM Alex Fishbein, who was the winner of the event on tiebreaks. He adds this victory to his win in the inaugural Denker event.

8/1/18 - BCE-297c

Another short one this week. In the battle of rook versus 3 far advanced connected passed pawns, White still manages to draw thanks to some stalemate tricks.