Wednesday, 24 January 2018

Trying out Stockfish 8

Having used a combination of old versions of Fritz and Rybka to error-check my chess analysis for years, I decided to give Stockfish 8 a go.  Ironically, this was prompted by Stockfish's much-publicised losses against Google's AlphaZero.  Yes, even bad publicity can be good.

I'm already finding that Stockfish sometimes disagrees with what Fritz and Rybka had to say on particular opening lines, and more often than not it tends to be right when I examine its suggestions closely.  For instance, I've previously examined the 13.Nxh7 sacrifice in Thiele-van Perlo, corr. 1987 in the Göring Gambit in the following position:

My previous examinations of the position suggested that 13.Nxh7 was dubious, and that 13.Ne6 was better, but a further examination with Stockfish suggests that 13.Ne6 is dubious because of 13...Bxe6 14.fxe6 and now the computer inconveniently points out 14...Ng8!, after which I can't see how White makes further progress.  Meanwhile, 13.Nxh7 appears to be sound, and may well be the best move in the position.  Thiele rather erred after 13...Kxh7 14.Bh5 g5 15.fxg6+, when after 15...Kg7 the g6-pawn blocks White's avenues of attack.  After instead 15.h4, it appears that White has at least enough for the piece in all lines.

I decided to feed Stockfish 8 a position that David Norwood used to show computers back in the 1990s, and which is sometimes thus known as the Norwood Position:

 Highlighting how far computers have advanced in the past 20 years, Stockfish 8 doesn't even look at the rook on a5, recommending that White shuffle the king, although it does erroneously assess the position at -17 pawns in Black's favour (the correct assessment is that it's a draw!).  If you enter 1.bxa5, it immediately gives mate for Black in circa 18 moves.

More challenging for the computer is if you replace the b-pawn with a bishop:

No, this wasn't originally my idea.  I can't recall where I first read it, but it is discussed in the Computer Chess News Sheet June-July 1994, so this might well be where the revised position originates from.  I recall feeding it to Fritz and Rybka some time ago and both computers insisted on grabbing the rook, but it might have changed with the latest commercial versions.

Stockfish 8 recommends 1.Bxa5 for a couple of minutes, assessing it as -5.2 pawns in Black's favour, and gives 1.Bb4 (the correct move) as -9.5 pawns in Black's favour, but then it picks up on 1.Bxa5 b4!, and within another couple of minutes it rejects 1.Bxa5 and gives 1.Bb4 followed by shuffling the king as best.  So even the revised version no longer stumps today's strongest computers.

There are of course still blockade positions that are even beyond Stockfish 8, but as computer AI continues to improve, they have to be more and more inventive.  I'm left wondering how AlphaZero, with its Monte Carlo method of calculation, would fare.  We might never know!

Wednesday, 3 January 2018

Kasparov plays the Mason Gambit

Happy New Year everyone!

Just stumbled upon a game from last August where Garry Kasparov, like Magnus Carlsen before him, wheeled out the Mason Gambit in blitz (1.e4 e5 2.f4 exf4 3.Nc3!?).

Unlike Carlsen's opponent, Karjakin did venture the critical response 3...Qh4+ but then after 4.Ke2 he went for the rather passive 4...Qd8.  As it was a blitz game he probably wanted to "play it safe" and the idea isn't completely without merit, for 4...d6 5.Nf3 Qd8 is one of Black's better responses, as discussed by John Emms in his 2000 book Play the Open Games as Black, giving a Fischer Defence where White has two extra tempi but one of them is the undesirable Ke1-e2.  As "brabo" discussed at the forum some time ago, the most critical response of all is probably 4...Ne7 covering d5.

However, after the immediate 4...Qd8, Kasparov's continuation 5.d4 Nf6 (5...g5? 6.h4 doesn't work for Black) 6.Bxf4 regained the sacrificed pawn and led to a rather interesting middlegame where White relied on a strong centre to compensate for the exposed position of the white king.

It would seem that Kasparov lost his way into the early middlegame and was lucky to get a draw, but fair play to him for continuing in the spirit of the opening and going all-out, which is usually the best way to swindle a win or draw in a blitz game. 

43...Qc6+ would have won for Black, with the idea 44.Kg1 hxg6.  Instead 43...Qd2+? was played (it was a blitz game after all!) and Kasparov managed to get a draw.

Earlier on, the computer offers 7.e5 as a reasonable alternative to the 7.Bg5 played in the game, and also suggests 7.Nd5, although I would find it difficult to psychologically justify allowing the opening of the e-file towards the white king with ...Nxd5, exd5.

Tuesday, 19 September 2017

Update on the Urusov

It's been a while, but I finally completed my update of the Urusov Gambit coverage at 
I've managed to get the ChessBase dynamic diagrams working, which allow viewers to move the pieces.  The new ChessBase game replayers is, I think, a significant improvement over the old one but I found that having multiple instances of the replayer on one web page caused glitches, so I have chosen to provide links to the annotated examples that are published using the One Click Publishing feature.

As for the assessment of the gambit, the accepted lines still seem to be holding up well, but of the declining lines, 4...Bb4+ does, as Michael Goeller suggested a while ago, appears to be the main problem at high levels, if Black aims for equality by striking out in the centre with a well-timed ...d5.  However, in the database, Black tends to follow up 4...Bb4+ poorly, and so the move is scoring only 41% for Black.  The highest-scoring reply for Black is the more well-known 4...Nc6 transposing to the Two Knights Defence (where Black is scoring 49%).  Black is scoring 44% after grabbing the bait with 4...Nxe4.

For White, if faced with a prepared opponent, there are some ideas for unbalancing the position after 4...Bb4+.  There is 5.c3 dxc3 6.0-0 0-0 (6...cxb2 7.Bxb2 and as in many such lines, it is unclear if White has two pawns' worth of compensation, but White's initiative is extremely dangerous) 7.a3!? (7.bxc3 d5), which gives some compensation, though I'm not sure if it is objectively enough.  More definitely sound but less in the gambit-style are 6.bxc3 d5 7.cxb4!?, and 6...Bc5 7.e5 d5 8.exf6 dxc4 9.Qxd8+.

I don't expect to be giving up the Urusov anytime soon, having had a lot of fun with it in practice, but in view of 4...Bb4+ as well as 4...Nc6, I don't expect it to catch on among grandmasters either.

Wednesday, 31 May 2017

A recent game in an unusual Morra Gambit Declined

I recently beat a higher rated player as White in an unusual line of the Morra Gambit Declined.

4...g6 looks like a slightly inferior way of declining the gambit, allowing White a classic two-pawn centre.  After 5.cxd4 the database gives 569 games with 5...Bg7 (probably best) when White is scoring 59.6%.

Over the board I spent a while deliberating over 5...d5 6.exd5 or 6.e5, and correctly selected exd5.  I was playing by analogy with some Göring Gambit Declined lines that I'd looked at before, where Black has to beware of the d4-d5 pawn push if White can get a knight out to c3 without it being hit by the pinning ...Bf8-b4.  I gave 6.exd5 Qxd5 7.Nc3 Qa5 in the notes, but most often played has been the retreat 7...Qd8, albeit with White still scoring a hefty 71.2%. 

I got very tempted by the possibility of trapping the black queen.  Fritz says that Black can survive, but admittedly has to walk a proverbial tightrope.  Overall I thought it was a pretty well-played game, though as usual at club level there were some mutual inaccuracies.

Meanwhile over at my gambits site I'm working on updating the Urusov Gambit coverage, as that is rather out of date at the moment.

Wednesday, 1 March 2017

Playing two sharp gambits in serious games for the first time- without knowing much theory!

I had a couple of recent serious games when, true to form, I played gambit lines, but it was the first time I had used them in serious games, and I haven't covered either of them at my website.  The games contain a fair number of mistakes, but they were 25 minute rapid games.

Game/Gambit #1 - The Geller Gambit

The more successful experiment was in the Geller Gambit (yes, I've also re-added 1.d4, 2.c4 lines to my repertoire, having been attracted to some of them back in my childhood).  1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 dxc4 5.e4 b5 is the normal move-order, but I stumbled into it via 1.d4 d5 2.c4 c6 3.Nc3 dxc4 4.e4 b5 5.Nf3!? (5.a4 is the normal move, according to the database, where White generally regains the pawn) 5...Nf6.

I had a close look at this line with someone from my local chess club back in 2014, but have to admit that I don't recall much of the theory.  My 6.e5 Nd5 7.Ne4?! was clearly inferior to 7.a4 and 7.Ng5, but was not punished.  Also, I could have got a strong attack with 13.f5 or 14.Nxe6 (both of which I actually looked at during the game, but didn't see far enough ahead).  The experiment paid off in the end though, and I have every intention of continuing to try out these Queen's Gambit lines.

My impression is that the Geller Gambit has been held suspect for many years, but that "the Ginger GM" Simon Williams has advocated it in some recent videos of his.  I associate Simon Williams particularly with the Dutch Defence (1.d4 f5) and some crazy queen sacrifices, notably this one.  He also tried the interesting deviation 1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.Nf3 dxc4 5.e4 b5 6.Qc2 against Andrey Sumets at Hastings 2013, but lost.

Game/Gambit #2 - Rubinstein Four Knights

The line goes 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Bb5 Nd4, from Black's point of view.  It's well-known to be a sound line for Black, where White often ducks out of the complications with 5.Nxd4 or 5.0-0.  I had recently taken this up in my online games, and sacrificed the pawn on e5 in several of them with good results.  However, I hadn't learnt many of the ideas behind the sacrifice of the pawn on e5, and so in this serious game played too "automatically" in the opening and didn't get enough compensation. Indeed, if I had found 10...Bg4! I would probably have gone on to win.

The games are available here: