OpenChess

Stockfish 8 - Houdini 5 , rematch with same openings

http://rybkaforum.net/cgi-bin/rybkaforu ... ?tid=31878
comments by Jeroen Noomen



Game 1, Sicilian. Stockfish 8 - Houdini 5 1-0 (match result: 1-0)
In the first game Stockfish quickly gains an opening advantage,
resulting in strong attacking possibilities. Houdini diverts the
attack by sacrificing an exchange, but the resulting ending is
winning for white. So the first strike comes from Stockfish.
Game 2, Sicilian. Houdini 5 - Stockfish 8 draw (match result: 1.5-0.5 SF)
In the return game Houdini converts its opening advantage into a
better ending and even goes two pawns up. However, the bishops
of opposite colours prevents white from winning the game, in the
end the draw is clear.

Game 3, Slav. Stockfish 8 - Houdini 5 draw (match result: 2-1 SF)
Houdini quickly gives up a pawn, but one move later it agrees this
is not such a good idea. Stockfish, however, allows black to
exchange knights to achieve bishops of opposite colours. When
rooks come off and the K-side gets blocked, it is clear the result
will be a draw. The game ends in a draw at move 133, after a lot
of shuffling (not included here).
Game 4, Slav. Houdini 5 - Stockfish 8 1-0 (match result: 2-2)
In the return game we get a very interesting position around move 25,
where SF thinks it is (almost) equal, while Houdini gives white the
advantage. Houdini proves right, it puts black's position under a lot
of pressure and scores a convincing win. The match is equal again.

Game 5, Ruy Lopez. Stockfish 8 - Houdini 5 draw (match result: 2.5-2.5)
This lively Zaitsev line of the Ruy leads to a very tense fight. Stockfish
gains the advantage and after some adventures it liquidates into what
looks like a completely winning ending. Eval goes up to over +4, but
in reality Houdini has a fortress and the position cannot be won.
Amazing. I give the game without engine data, because otherwise
I would exceed the maximum number of characters in one posting.
And I wanted to post the full game, to show it really ended in a draw.
Game 6, Ruy Lopez. Houdini 5 - Stockfish 8 draw (match result: 3-3)
The Zaitsev return game is more level, Stockfish equalizes and reaches
a well known drawn ending, where white has an h-pawn and the bishop
of the wrong colour.

Game 7, King's Indian. Stockfish 8 - Houdini 5 draw (match result: 3.5-3.5)
The Mar del Plata variation of the King's Indian always leads to exciting games,
with white attacking the Q-side and black trying to force an attack on the K-side.
This game is no exception. It seems Houdini's attack as black is running out
of steam and Stockfish is creating winning chances on the Q-side, but black's
active play holds the balance: draw.
Game 8, King's Indian. Houdini 5 - Stockfish 8 0-1 (match result: 4.5-3.5 SF)
The TCEC 9 superfinal didn't produce a black win (although it was close in
a couple of cases). In this match we can celebrate the first black win already
in game 8! Stockfish's attack after the pawn sac g4-g3! quickly gains steam
and black scores a very convincing win.

Game 9, French. Stockfish 8 - Houdini 5 draw (match result: 5-4 SF)
In the Chatard-Alekhine variation of the French it seems Stockfish has a nice
advantage after 16.Nd6, but Houdini quickly gives back its pawn plus,
solves the problem of the black king and achieves a draw without too
much difficulty.
Game 10, French. Houdini 5 - Stockfish 8 draw (match result: 5.5-4.5 SF)
In the return game we see Houdini pressing for the win. White wins the
exchange, but SF's active knights and the extra pawn hold the balance: draw.

Game 11, Grünfeld Indian. Stockfish 8 - Houdini 5 draw (match result: 6-5 SF)
White looks somewhat better after the Modern Grünfeld with 3.f3, but Houdini
is able to liquidate into an ending where it has 2 strong bishops. Black even
shows some advantage, but it turns out the ending is level and therefore a
draw is the correct result.
Game 12, Grünfeld Indian. Houdini 5 - Stockfish 8 1-0 (match result: 6-6)
A very long game, which I'll give without engine data. Houdini is pressing
with white, but it seems Stockfish can hold. Far into the ending, with time
pressure looming, Houdini suddenly sees the win with 113.Rd4 and a +1.76 eval.
Stockfish takes a couple of move extra to see the danger, but then it is
too late. The match is even again!

Game 13, Caro-Kann. Stockfish 8 - Houdini 5 1-0 (match result: 7-6 SF)
In the 3.e5 Advance variation of the Caro-Kann Stockfish gets a nice
advantage after the opening, but Houdini defends and in the end we
get a strange ending RRB vs RR. This should be drawn, but suddenly
Stockfish shows 80.Rd8 with a +6 score! A few moves later the game
is over. Stockfish takes the lead again.
Game 14, Caro-Kann. Houdini 5 - Stockfish 8 draw (match result: 7.5-6.5 SF)
The return game is not very eventful. Houdini enjoys a space advantage
and is able to press, but apart from a lot of shuffling not much happens.
Hence a draw is the inevitable result.

Game 15, English Hedgehog. Stockfish 8 - Houdini 5 draw (match result: 8-7 SF)
In a typical hedgehog position Houdini suddenly gets aggressive with 28... f5.
This alters the structure of the game completely. Black's pieces come to life,
Stockfish wins a pawn, but black's active counterplay is enough to keep the balance.
Game 16, English Hedgehog. Houdini 5 - Stockfish 8 draw (match result: 8.5-7.5 SF)
In the return game Houdini allows black to play the freeing 19... b5!, which
equalizes immediately. White cannot keep the plus pawn and the game
quickly fizzles out into a draw.

Game 17, Sicilian Dragon. Stockfish 8 - Houdini 5 draw (match result: 9-8 SF)
In a main line Sicilian Dragon, Yugoslav attack, Stockfish acts surprisingly timid.
Houdini has no problem to equalize and the game ends in a disappointing draw
by repetition. You would expect more from such a sharp line!
Game 18, Sicilian Dragon. Houdini 5 - Stockfish 8 draw (match result: 9.5-8.5 SF)
The return game in the Dragon sees more action. Houdini also plays the white
position very timid and Stockfish takes the initiative. Black wins two pieces
for a rook, but in the ending this advantage is not enough to win the game.

Game 19, Nimzo Indian. Stockfish 8 - Houdini 5 draw (match result: 10-9 SF)
Houdini plays the Hubner variation very passively and Stockfish enjoys a nice
space advantage. But then nothing happens anymore. After endless shuffling
the game ends in a draw. I'll give the game without engine data.
Game 20, Nimzo Indian. Houdini 5 - Stockfish 8 draw (match result: 10.5-9.5 SF)
The return game is more open and this time Houdini enjoys an advantage.
But history repeats itself: the position gets blocked and when the heavy
pieces are traded nothing happens anymore: draw.

[not necessarily exacltly the same openings as in superfinal, but similar]

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Game 21, King's gambit. Stockfish 8 - Houdini 5 1-0 (match result: 11.5-9.5 SF)
A truly crazy game in the King's gambit. Stockfish quickly equalizes from a
slightly worse position and pushes a white pawn to a7. That forces Houdini
to place a knight on a8 passively. Practically, white is now playing with an
extra piece. When the queens and one pair of rooks are exchanged, the
white advantage proves decisive. Stockfish thus repeats its win in this line
compared to the TCEC 9 superfinal.
Game 22, King's gambit. Houdini 5 - Stockfish 8 0-1 (match result: 12.5-9.5 SF)
In the return game Houdini quickly goes astray by playing 11.Nxg5?, with an
eval of just -0.18 and played after only 45 seconds (d=21). Stockfish immediately
jumps to over +1 and the game seems already lost for white. SF picks up a piece
and hence wins the King's gambit duel by 2-0.

Game 23, Slav. Stockfish 8 - Houdini 5 1-0 (match result: 13.5-9.5 SF)
The Bronstein variation of the Slav (5... Bg4) features interesting
complications. Stockfish wins an exchange, but the wN on h8 looks
in danger. However, black doesn't manage to capture it: the knight
escapes and white wins with his material advantage.
Game 24, Slav. Houdini 5 - Stockfish 8 draw (match result: 14-10 SF)
The return game in this line is also very interesting. Look at the
position after 22... Nd4: quite murky and difficult to assess. Houdini
seems to be better, but Stockfish manages to win back the pawn and
the game ends by a repetition of moves.

Game 25, Modern Defence. Stockfish 8 - Houdini 5 draw (match result: 14.5-10.5 SF)
Stockfish launches an attack directly after the opening, the position after 15.f5
looks tense and dangerous for black. Houdini defends well and gives up two
rooks for a queen to slow down the attack. White still looks better, but black's
strong defensive play secures the draw.
Game 26, Modern Defence. Houdini 5 - Stockfish 8 draw (match result: 15-11 SF)
In the return game Houdini plays more carefully and castles short. After
13... Nxc6 the position is more looking like a calm Sicilian Dragon. Black
has no problems equalizing and after lots of exchanges the game ends in a draw.

Game 27, Chigorin Defence. Stockfish 8 - Houdini 5 1-0 (match result: 16-11 SF)
After opposite castling by Stockfish an interesting position arises, that looks
close to equal around move 30. But then Houdini starts to play passively/planless
and within a few moves the white passed a-pawn becomes very dangerous. This
is enough to tip the game in white's favour.
Game 28, Chigorin Defence. Houdini 5 - Stockfish 8 draw (match result: 16.5-11.5 SF)
In the return game we see a familiar pattern: Houdini plays more carefully and
Stockfish quickly equalizes. The game seems to become more interesting
around move 22, but then a lot of pieces are traded and what is left is a drawn
rook ending.

Game 29, Philidor Defence. Stockfish 8 - Houdini 5 1-0 (match result: 17.5-11.5 SF)
Black quickly gives up the center and at move 22 white enjoys a very pleasant ending.
At move 31 Houdini sees no other alternative but to sacrifice a pawn, but there is no
compensation and Stockfish has no trouble to bring its advantage home.
Game 30, Philidor Defence. Houdini 5 - Stockfish 8 draw (match result: 18-12 SF)
Stockfish also gives up the black center quickly and Houdini enjoys a pleasant edge.
18.e5 doesn't look right, though. The pawn structure becomes symmetrical and after
32 moves black is close to equality. Bishops of opposite colour appear and from that
point it is clear the game will end in a draw.

Game 31, King's Indian. Stockfish 8 - Houdini 5 draw (match result: 18.5-12.5 SF)
In the King's Indian Sämisch Stockfish looks on its way to another white win.
White's attack looks very dangerous and Houdini has no counterplay. But white
doesn't find anything better than a liquidation into a rook ending, that black can
hold: draw.
Game 32, King's Indian. Houdini 5 - Stockfish 8 1-0 (match result: 18.5-13.5 SF)
In the return game Stockfish allows Houdini to exchange the light squared bishops
and plant a knight on e4. White has a clear advantage and improves his position
move by move. Stockfish gets no counterplay and Houdini scores a convincing victory.

Game 33, Sicilian. Stockfish 8 - Houdini 5 1-0 (match result: 19.5-13.5 SF)
Instead of playing the usual and active 11... Qb6, Houdini embarks on a
passive line of play in the Sicilian Rauzer and quickly gets into difficulties.
Stockfish gets a huge advantage and 28.e5! is a nice way to open up the
position. Black is defenseless against the active white pieces.
Game 34, Sicilian. Houdini 5 - Stockfish 8 draw (match result: 20-14 SF)
Houdini's opening play is too timid and already before move 20 Stockfish
enjoys a slight edge. Nevertheless, Houdini defends well and manages to
trade some pieces, after which the ending is level again. A draw is the
logical result.

Game 35, Tarrasch. Stockfish 8 - Houdini 5 draw (match result: 20.5-14.5 SF)
In a Tarrasch Defence Houdini sacrifices the isolated d5-pawn and gets a
strong pair of bishops as compensation. There is not much white can do
to relieve the pressure and Stockfish has to be satisfied with a draw.
Game 36, Tarrasch. Houdini 5 - Stockfish 8 draw (match result: 21-15 SF)
In the return game Houdini refrains from attacking the d5-pawn and goes
for the pair of bishops: 16.Nxe6. This is the same plan Smyslov used in
the Candidates final against Kasparov, but theory agrees it doesn't give
white much. This is confirmed by this game: by move 27 black has an
equal position and the game ends in a logical draw.

Game 37, Ruy Lopez. Stockfish 8 - Houdini 5 draw (match result: 21.5-15.5 SF)
In the Schliemann Ruy Lopez Stockfish goes for a line that wins a pawn, but
black has good compensation. After some exchanges we are left with a rook
ending that looks a little better for white. Houdini defends the black position
without much trouble, hence a draw is the final result.
Game 38, Ruy Lopez. Houdini 5 - Stockfish 8 1-0 (match result: 21.5-16.5 SF)
Houdini pulls one back by winning the return game in the Schliemann Ruy
convincingly. White has a nice edge and when Stockfish misses the brilliant
30.f4! the black position goes downhill rapidly.

Game 39, Trompovsky. Stockfish 8 - Houdini 5 draw (match result: 22-17 SF)
In the 'Tromp' we see a pattern that happens quite often in engine-engine games:
the position becomes blocked, with no serious pawn lever left to play for a win.
After some shuffling we get some action in the end, but the draw was never in doubt.
Game 40, Trompovsky. Houdini 5 - Stockfish 8 draw (match result: 22.5-17.5 SF)
The return game in the Trompovsky is more interesting: we get a position with
potential to play for a win, but Stockfish sacrifices an exchange to steer the
game towards a draw.


first 40 games:

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