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Normal Topic Black replies to C18 Armenian 6. b4 cxd4 7. Qg7 (Read 4339 times)
MartinC
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Re: Black replies to C18 Armenian 6. b4 cxd4 7. Qg7
Reply #3 - 01/25/15 at 08:48:47
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g6 isn't something you want to play unless you really have to. Unpleasant long term weaknesses.

Kf8 might be more plausible - very respectable after 5 .. Bxc3+ etc - I'm not sure why you'd play 5.. Ba5 if wanting to go there though. All those open queenside lines don't look very helpful.
  
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Bibs
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Re: Black replies to C18 Armenian 6. b4 cxd4 7. Qg7
Reply #2 - 01/25/15 at 07:51:43
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The experts say 'too early for software, try later'.
  
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gauss
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Re: Black replies to C18 Armenian 6. b4 cxd4 7. Qg7
Reply #1 - 01/25/15 at 05:29:37
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I don't know much about the Armenian French, but in general I would be caution against relying too much on engine evaluations in the opening.
  
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mwalimu
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Black replies to C18 Armenian 6. b4 cxd4 7. Qg7
01/25/15 at 01:02:30
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Let me say up front that I'm not a particularly strong chess player. In my younger days I studied it, played tournaments for a while, and got my rating up to about 1600.

More recently my interest has taken the form of running tournaments between chess engines on my computer. I also like to replay grandmaster games with the best chess engines running in analysis mode. In Arena I can load up several of them at once to see what they think is the best move at any point in the game. Many of these engines have a multi-PV feature; it's normally turned off when I have them playing against each other, but for analysis mode, I'll set to 5. What that means is that it's not just showing me what it thinks is the best move, but the 5 best moves. Results are mixed - sometimes the analysis bears out how truly brilliant the players were, while other times a game held up as a shining example turns out to be flawed.

In the early moves, I'll also follow along using online databases, and it can get interesting when some of the moves favored by the chess engines are ones that are infrequently or never played in human. I've wondered if anyone has ever tried traversing these databases and in positions that have been reached a sufficiently large number of times, had chess engines analyze the positions to see if there are any good moves that have rarely or never been played.

Recently while replaying a 1960 Fischer-Tal game, I encountered just such a situation. It happens in the following position:
C18 French, Winawer, Armenian
1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. e5 c5 5. a3 Ba5 6. b4 cxd4 7. Qg4
FEN: rnbqk1nr/pp3ppp/4p3/b2pP3/1P1p2Q1/P1N5/2P2PPP/R1B1KBNR b KQkq - 1 7
ChessTempo has over 400 games that have reached this position, and ChessBase has almost as many. Ne7 is the standard reply, played in about 90% of the games, with Kf8 played in most of the rest and Qc7 in a very few. But according to the chess engines that were analyzing during my play through, Kf8 was the better move.

So out of curiosity, I had eleven different chess engines with multi-PV capability analyze this position. The engines used all have CCRL ratings that are above 3000 (or just barely below it). I let each one run for a minimum of one hour with multi-PV set to 5. The results bore out what I had discovered earlier, that Kf8 was the better move. But an even bigger surprise was that Ne7 wasn't even the second-best move; it was only third-best. The second best move was g6, and neither of the above-mentioned online databases has even a single game where this was played.
Here are the results in tabular form (0 is the best move; the others show how many centipawns behind):
Engine Kf8 g6 Ne7
Stockfish 5 0 -29 -59
Fire 4 0 -12 -44
Gull 3 0 -35 -72
Equinox 3.30 0 -16 -38
Critter 1.6a 0 -20 -28
Komodo CCT 0 -30 -33
Bouquet 1.8 0 -2 -16
Houdini 1.5a 0 -17 -22
BlackMamba 2.0 -2 -6 0
Texel 1.04 -14 0 -19
Rybka v2.3.2a -1 0 -14
As you can see the results are not unanaimous. One liked Ne7 best, two liked g6 best, and one that liked Kf8 thought Ne7 was better than g6. But despite the variability, this is actually better consensus than I usually see in this sort of multi-engine analysis.

By the way, the engines all agreed on the fourth-best move, which was g5. They also all rated it variously between 100 and 182 centipawns worse than the best move, which is enough to treat it as not worth considering.

What about 7. .. Qc7? It looks like a good counterattacking move, threatening Qxc3+, but it turns out it's a blunder. For white the best defense is a good offense. After 8. Qxg7! Qxc3+ 9. Kd1 Qxa1 10. Qxh8 white gets either the bishop on a5 or knight on g8, but now black's queen is stuck in the corner, white has an easier task getting his other pieces out into play, and by the time black gets his act together, white will have nabbed another pawn or two.

Since 7. .. Ne7 is the most played move I won't spend a lot of time on it. A cursory chess engine analysis of the main line, 8. bxa5 dxc3 9. Qxg7 Rg8 10. Qxh7 Nbd6, suggested these moves are best play, although on black's 10th move some of the less-frequently played alternatives - Qc7, Qxa5, Nd7, Bd7 - are very close and might merit further study.

The three best replies to 7. .. Kf8 are 8. Nb5, Qxd4 and bxa5 (though there are a few others that are not obviously bad such as Bg5, Nf3 and Nce2). Of these three, Qxd4 shows up far less in the online databases, even though it may be as good as the other two. And after 8 bxa5 dxc3, white's best is probably Qb4+ whereas the databases show Nf3 or a4 are usually played here. Some possible continuations of these moves:
8. Nb5 Bb6 9.Nf3 Nc6 10. Bb2 Nge7 or a6 or Nh6
8. .. a6 9. Nxd4 Qc7 10. Qg3 Bb6 11. Bb2 Nc6
  9. bxa5 axb5
8. Qxd4 Bb6 9. Qf4 Ne7 followed by 10. .. Ng6
8. bxa5 dxc3 9. Qb4+ Ne7 10. Qxc3 Nbc6 11. a6 or Bd2
  9. Nf3 or Bd3
  9. a4 Nc6 10. Ba3+ Nge7

Finally we get to the almost unexplored move, 7. .. g6. White has several options. Best play seems to be 8. Nb5 Bc7 9. Bg5 Qd7 10. Nf3 Nc6 though the resulting position could be reached by a couple of other transpositions - 8. Bg5 Qd7 9. Nb5 Bc7 10. Nf3 Nc6 or 8. Nb5 Bc7 9. Nf3 Nc6 10. Bg5 Qd7. I would go so far as to label this the "signature position" that will determine whether 7. .. g6 is a move human players will want to consider.
FEN: r1b1k1nr/ppbq1p1p/2n1p1p1/1N1pP1B1/1P1p2Q1/P4N2/2P2PPP/R3KB1R w KQkq - 6 11
Possible continuations would include:
11. Nxd4; 11. .. h6 seems to be best for black, though Nxd4, a6, a5, f6, and possibly Bxe5 merit further consideration. After 11. .. h6 12. Bd2 looks best, though Be3 and Bf4 are close behind, probably followed by 12. .. Nge7. Also notable is 12. Nxc6 hxg5 13. Nd4
11. Nxc7+ Qxc7; 12. Bb5 or Bd3 or Rd1 are all possibilities, and maybe Be2 or Qg3
11. Qg3 or Bf4, e.g. 11. Qg3 Bb8 12. Ndxb4 Nxd4 13. Nxd4
White could also develop with Be2 or O-O-O or Rd1

Black has other alternatives to some of moves 8-10 above. After 8. Nb5 Bc7 9. Bg5 Qd7 10. Nf3 black could play 10. .. h6 11. Bf4, Bd2, Nxc7. Or if white starts with 8. Bg5 black could play 8. .. Qc7 followed by 9. Nb5 Qxe5+ 10. Kd1 with possible replies d3, Bb6, Nc6, a6, or h5. There are other black alternatives besides these
  9. Nf3 Nc6 10. Bg5 Qd7 (transposition of above)
8. Bg5 Qd7 9. Nb5 Bc7 (transposition of above)
8. .. Qc7 9. Nb5 Qxe5+ 10. Kd1 with possible replies d3, Bb6, Nc6, a6, h5

Finally, white has other possibilities to consider on move 8. Three of these, and some of the possible continuations:
8. Qxd4 Nc6 9. Bb5 Bb6 10. Qd3 or Qf4
8. .. Bb6 9. Qf4 a6 (or f6 or Nd7 or Ne7)
8. Bb5+ Bd7 9. Qxd4 Bb6 10. Qf4
  9. Bxd7 Qxd7 10. Qxd4 Bc7
   9. .. Nxd7 10. Nxd5 Nxe5 11. Qxd4 Qxd5 12. Qxd5 exd5 13. bxa5
8. Na4 Bd7 9. Nc5 Qc7 11. Qxd4 Bb6
   9. .. Bc7 10. Nf3 Nc6 11. Bf4 h5
    10. Bg5 Qc8
    10. Nxb7 Qc8 11. Nc5
8. .. Bc7 Nf3
Most other replies lead to 8. .. dxc3 9. bxa5 Qxa5 (essentially same if 8. bxa5) and white is arguably not as well off.

So, what say the experts about all of this?
  
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