Sunday, December 24, 2017

December 2017 Tactical Training: Part 2

Merry Christmas, everyone!

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Thursday, December 21, 2017

Boris Spassky's Greatest Games

As promised a really long time ago, I wanted to write an article to pay tribute to Boris Spassky, who has been portrayed as the victim many times in my previous writings (such as my series on Fischer and Petrosian). While he didn’t have the fiery drive of Fischer or the iron defensive skills of Petrosian, Spassky was reputed for his universal playing style, which made him very adaptable. His greatest strength lay in the middlegame, where his tactical acumen made him a dangerous and aggressive player.

One of Spassky’s unusual opening favourites was the King’s Gambit, a line that is rarely seen in top-level play. This choice had served him well, as we shall see in the following two examples. In our first game, the Russian used a spectacular rook sacrifice to invade via the f7 square, a move which was described as comparable to the Evergreen Game:

Boris also used the King’s Gambit to great effect against his biggest rival: Bobby Fischer. While we already know what happened between the two of them at the historic 1972 encounter, here is a lesser-known clash 12 years before, where Spassky emerged victorious in a sharp, romantic-style game:

It is worth noting that prior to the 1972 match, Spassky had a positive head-to-head score against Fischer, with two draws and three victories in favour of the Russian! The next position is another encounter between these titans where Boris came out on top. I originally did not intend to include the game in this article, but the final tactical combination is so elegant that I cannot resist showing it as a puzzle:

You can see the entire game over here.

While the earlier examples were showcases of Spassky’s tactical mastery, he could also play strong positional chess if required. In Round 5 of the 1969 World Championship, Spassky demonstrated how a well-supported passed pawn could become so powerful that not even Iron Tigran could stop it:

Spassky (left) vs Petrosian, 1969

Not surprisingly, this was also the match which Spassky won to cement his position as the tenth World Champion.

“In my country, at that time, being a champion of chess was like being a King. At that time I was a King … and when you are King you feel a lot of responsibility, but there is nobody there to help you.” - Boris Spassky

Even in his later years, Boris Spassky was still a force to be reckoned with. Our final example illustrates his defensive prowess in a difficult position, played against a young and rising Garry Kasparov:

At the time of writing, Spassky is currently the oldest living world champion. The following webpage shows excerpts from an interview in 2014, where he fondly recollects his earlier days and what chess means to him.

Spassky (right) and Anand, Sochi 2014 (Photo by Anastasia Karlovich)

Like so many great names before and after him, Spassky’s contributions to the royal game are immeasurable, and he definitely deserves a place alongside Fischer and Petrosian as one of the greatest chessplayers of the 20th century.

“I still look at chess with the eyes of a child” – Boris Spassky


Tuesday, December 12, 2017

AlphaZero vs Stockfish part 1

As we all probably know by now, AlphaZero has played against Stockfish 8 for 100 games. Both sides have one minute per move, probably due to AlphaZero lack of time management yet. AlphaZero did not lose a single game to Stockfish and won 28 games. This type of result is almost never heard off in computer chess tournaments, it shows how AlphaZero developed 'intuition' on which positions to calculate, instead of an extremely fine-tuned alpha-beta search. AlphaZero searches just 80 thousand positions per second, compared to 70 million for Stockfish. However, its deep neural network focuses much more selectively on the most promising variations, similar to how a human would calculate[1], thus AlphaZero's games may seem quite human-like in nature. In this article, I'll be showing the first 5 games that are made public[2].
Board 1: Piece activity

AlphaZero's play is quite human-like, probably due to the way it searches. It also likes to immobilize white's pawns - a theme to be repeated many times.
The sacrifice by stockfish seemed quite promising at first, but it was not able to attack as AlphaZero's pieces are much more well placed in the middlegame compared to Stockfish's pieces. The games will start to get more interesting from here.
Board 2: Light square weaknesses

This game is extremely Nimzovich-like, overprotecting squares. In this Ruy Lopez variation, white exchanges away the light square bishop for a knight, hoping to exploit the doubled pawns, seems like keeping the light square bishop would have been a better variation, instead of having pawns on e4 and c4 as light square targets.
AlphaZero is playing chess more positionally, and less engine-like, similar to how people used to play against engines, until computational power took over.
Board 3: Dark square weaknesses

A middlegame zugzuang, how often do you see that. AlphaZero is really good at it's positional games, exploiting a kingside fianchetto structure when black does not have its dark square bishop, and then 'trapping the queen' and completely paralyzing black, forcing black to lose material by zugzuang.
The sight of having all the major pieces just sitting on your sixth rank dark square weakness looks extremely intimidating, and then having your pieces paralyzed, an extremely torturous game for stockfish.
The pawn sacrifice will happen on another game, suggesting that sacrificing that pawn for activity is possibly dangerous for black playing QID. Black may be able to draw by returning the d pawn which the queen and rook were applying pressure on even after weakening the dark squares.
Board 4: Backwards pawns

AlphaGo is really good at exploiting weaknesses, only a bishop of the wrong color and a backwards pawn and black crumbles. Stockfish is constantly getting positionally outplayed, surprisingly it survives the endgame for quite some time. It is also nice to have a French Defense game where black loses positionally(really dislike playing against french).
Game 5: Misplaced pieces

Looks like the 'Kasparov pawn sac' in QID is working quite well, immobilizing the queenside. 8...c6 was probably a blunder as it allows white to attack the d6 square with both its knights and queen.
AlphaZero repeatedly moves the same piece many times in the opening to misplace black's pieces, instead of development, misplacing pieces seems to be of higher importance than development here.
The QID is constantly losing to pieces being inactive from the pawn sacrifice, either Kasparov refuted QID many years ago and now AlphaZero also found the refutation or black should prevent the gambit by 6...d5! instead of O-O. We'll have to see AlphaZero play against itself in QID to know with higher confidence.
AlphaZero playing style is similar to William Steinitz for the middlegame and Capablanca/Bobby Fisher for the endgame. It's opening choice aim to get a positional advantage to completely outplay positionally in the middlegame, forcing weaknesses.
Stockfish has been positionally destroyed in all of the games, most likely due to AlphaZero learning to play more positionally than just brute force calculation. Brute force calculation is vulnerable to the horizon effect, trying to use an engine to evaluate shows this effect quite nicely, it gives stockfish an advantage or rate it as a draw until a few minutes later where it gives AlphaZero an positive score. We may be seeing more positional games in grandmaster games soon.
In part 2, I'll be showing the other 5 games and hopefully more games will be out by then.
References so I don't get sued:
[1] arXiv:1712.01815v1 [cs.AI]
[2]Google's AlphaZero Destroys Stockfish In 100-Game Match

Monday, December 11, 2017

December 2017 Tactical Training: Part 1

With Christmas coming soon, it's time to give some early presents. Have fun!

Thursday, December 7, 2017

Random Games, Random Opportunities

With more time on my hands, it is a good period to clear the backlog of unanalyzed games in my database. Here I will show three friendly games played during the various meetups throughout the semester.

Game 1: The curse of isolated pawns

Our first game was a seemingly peaceful, casual game during NUS IGC training… until my training partner pointed out how close I was to scoring a win from an isolated-pawn position.

Put the following position in a puzzle, and it shouldn’t be difficult to spot the winning combination:

Now see the actual game and wonder how I manage to throw away such a nice position:

What can we learn from this game?
  • Being cautious is good, but too cautious makes you miss chances
  • Avoid hanging your own pieces, or they may be the target of potential tactics
  • When playing an advantageous position, don’t make your opponent’s life easier by exchanging off key attacking pieces!

Game 2: The curse of backward pawns

So how salty was I over that missed chance in Game 1? Very, but not as much as the next game, where what looked like a completely winning position for Black turned into an equal fight, and concluded as a dreadful blunder. Admittedly it was a 15+10 rapid game where anything could happen, but still, the saltiness is high in this one:

I'm sorry, I will work hard to redeem myself!

 What can we learn from this game?
  • Time-trouble is a b***h
  • At the rate that I am throwing away won games, it is probably time to write a 2nd edition of my Chess Patzers articles.
  • To play against backward pawns, first prevent them from advancing by fixing them with your own pawns, before using the square in front of them as “outposts” for your pieces

Game 3: The curse blessing of the Greek Gift!

Is it time to redeem myself? Here is a third game from the Asia Square meetup, and thankfully, this time I DID spot the winning blow!

It ain't everyday you get to send gifts like this!

A game well-played, but I will still need to go back and work harder on tactics. Until the next game, then!

By Giovanni Domenico Tiepolo - Own work, Public Domain,