12

All of White's other pieces are placed well except the Bishop on f3. If Black moved the a8 rook back and forth then White would probably like to play Rg3, Bg2-h3, and maybe Rg3-e3. Simply put Rg3 increases the scope of the rook and the bishop.


12

The knight on h5 is pinned to a rook, and faced with the potential threat of g4. To unpin this knight, Black should play Rh7, so that the knight is free to go to f6 (where it will protect the rook). [FEN "1k5r/p1p2pq1/2n5/1p1p3n/1P1Pp2Q/P1P1P1P1/1B1K2B1/7R b - - 0 1"] 1...Rh7 2.g4 { This move is just for illustration, and probably not best. } Nf6 I would ...


11

White does indeed fork the king & rook after Nc7+ - but after Nxa8, the knight is not escaping, so Black is at worst even on material. [FEN ""] 1. d4 c5 2. Nf3 cxd4 3. Nxd4 Nc6 4. Nc3 e5 5. Ndb5 Bb4 6. Bg5? Qxg5 7. Nc7+ Kd8 8. Nxa8 After something like ...b6 followed by Bb7, the knight's a goner. White can get at most one pawn for the knight (after ...


11

I agree with the other two answers, but I feel like I also need to comment on the beginning of the game since there was A LOT more important stuff there than just the answer to why Qxg5. This is very similar to a Kalashnikov Sicilian by transposition with the exception that the knight is on c3 instead of a pawn on e4, but the ideas are very similar. In ...


9

Part of the problem with Bc5 is that they can respond with Na4, which threatens the bishop and grabs the tempo. Be7 isn't great because its range is inhibited by the knight and it impedes the kingside rook's power on the e file after you castle. Bd6 is nice because it is protected by the pawns, the bishop can be retreated to b8 or c7 while still controlling ...


8

In the present position black cannot move the knight, and it appears white is threatening to attack it with g4 but in fact if white plays g4 he won't be able to capture the knight with the pawn without losing the bishop n g2. ...Rh7 is one way to allow the knight to move away to f6 but it is not necessary to play that right away and you could play a move ...


7

Why is the engine evaluating against bringing more attackers in this position? That's not what it is doing. It is evaluating against blundering a draw. After Rb8 your queen has nowhere to go apart from allowing a repetition. If you play Qxa6 you are just a piece and a pawn up for no compensation. [FEN "r2qk2r/pQpbbppp/n2p1n2/3Pp3/4P3/2N1BN2/PPP2PPP/...


6

In addition to Allure's comments. Two pieces is favourable to a rook in a position like this where there's no clear squares for the a8-rook to attack, but lot's of squares in the center for the two minor pieces to control. Black is definitely better after the exchange.


6

There were attempts back in the 1980s to write chess engines with knowledge bases that would pick candidate moves like humans, but they were unsuccessful. The problem is that human pattern matching is difficult to put into words, so creating the rules for the knowledge base was extremely difficult. Training a neural network to pick candidate moves seems ...


5

Bd6 has two big advantages that haven't been mentioned. The first is that it protects the b8 square for your rook. Your rook naturally belongs on the half-open file, and White really wants to play Bf4 to keep you from doing that. (You can put your bishop on d6 later if that happens, but you've wasted a tempo and exchanging bishops makes it easier for the ...


5

Bd6 is the most active square. No, there's not an immediate threat but it does attack h2 which could turn into something later. Be7 is too passive. It's not smart to "protect against pins" that haven't even happened yet. There's lots of unpin combinations that actually lead to the pinning side being worse. Also, white can't really capitalize on a ...


4

e7 is a very passive square for the bishop. Since White is expected to castle on the kingside, there is no reason not to prefer ...Bd6 over ...Be7. The pin on the f6 knight is not too much of a problem precisely because a ..Bc7, ..Qd6 continuation is always on the table. ...Bb4 has a similar problem as ...Be7 because after 0-0 the bishop is doing nothing on ...


4

You might take a look at Giraffe which was recently in the news: https://thestack.com/iot/2015/09/14/neural-network-chess-computer-abandons-brute-force-for-selective-human-approach/ The hype is that in 3 days it taught itself the game and reached IM level. On the other hand the research is at http://arxiv.org/abs/1509.01549


3

It seems like e3 is the square that the Rook on g3 is heading for - after moving the Bishop on f3. (somewhere out of the way) This gives the g3 Rook certain access between the two f-file pawns. The idea is to allow both Rooks to work together on the e-file.


3

I'd like add details to @Ian_Bush's answer on Giraffe. In @Ian_Bush's answer, it's noted that Giraffe doesn't use brute-force computation. This is not right, because Giraffe is still an alpha-beta (nega-max) engine. The only difference to a standard engine is that the evaluation function is tuned automatically by deep-learning. Therefore, the engine learns ...


3

There is a nice story attached to the 1960 Tal-Botwinnik match. They adjourned after 40 moves and began analysing the game so far. Botwinnik had got his Queen offside and Tal had numerous exciting sacrifices to look at but had not played any of them. In the analysis, Tal was trying to find out if any of them would have worked, but noticed after a while that ...


2

Its sort of debatable if you can call a heuristic based search and evaluate approach as brute-force. Most of top-tier chess engines today follow a rules-based approach to evaluate a position and a rules based search function to prune moves. This is actually not guaranteed to pick the "global optimal" move, however these moves are good enough for purpose. In ...


2

Claude Shannon proposed two types of algorithms for creating chess engines. A "type A" engine examines all possible moves to some finite depth, minimaxes the tree, and then plays the move with the highest evaluation from the minimaxed tree (a.k.a. brute force). Type B engines limit their search to only a subset of possible moves based on some criteria. I ...


1

when the pawns are on c6 and d5 that means that your dark bishop is your best bishop after c6 and d5 the dark square around them are weak and the bishop takes control of those square. the bishop on e7 is not controling alot of square on c5 and b4 it can get kicked around with a3 b4 or Na4. I am 2100 take that into account.


1

I assume you're wondering about the speed of calculating moves. I'm not sure how you would go about figuring out the max #moves a GM can calculate (I guess the experiment runs until they fall asleep?). I'm an FM and I can calculate a couple of moves per second (1-3), assuming the calculation is trivial enough. For more complicated positions where I need to ...


1

Firstly, I would like to point out, you cannot figure out how good is the move, because no move can improve position, only make it worse. And the winner is usually the one who managed to "destroy" his position less than the opponent. So the questions should be: "how bad a move is"... =) Secondly, I believe you cannot actually score a move. You can only ...


1

This is a very complicated position. No obvious winning plans. White has the bishop pair and much more space, but the f2,f4 and h5 pawns are all isolated, and black is very compact and defends everything. Stockfish shows +300cps advantage, but is not able to convert until maybe move 25 or so, frequently even reaches fortresses. So, I am not certain what this ...


1

This is what I do after I get out of preparation: Check for threats against me If none or I judge them to be insignificant: Look for weaknesses in the opponents position and then look for tactics to attack them If none: Move a or h pawn (to create weaknesses and per Aronyan's advice: "If you don't know what to move, move a or h pawn") ...


Only top voted, non community-wiki answers of a minimum length are eligible