Move 12 discussion: Everyone vs stockfish

[MooMoo2]

The poll for move 11 just closed, and the most popular move was Nfd4. Stockfish responded with 11...O-O, and the FEN is:
r2q1rk1/pp2bppp/5n2/3p4/3Nn3/1N6/PPP2PPP/R1BQ1RK1 w - - 4 12

Game so far: 1.e4 e6 2. d4 d5 3. Nd2 c5 4. Ngf3 Nf6 5. exd5 exd5 6. Bb5+ Bd7 7. Bxd7+ Nbxd7 8. O-O Be7 9. dxc5 Nxc5 10. Nb3 Nce4 11. Nfd4 O-O

[Brian-E]

The immediate key issue now, to my mind, is that Stockfish has given priority to quick castling and has not done anything about our minor threat of 12.Nf5 which allows us to force an exchange of the knight for Black's more valuable bishop. I think this is good for us, leaving us with slightly the better pair of minor pieces still on the board, while our knight on b3 is still poised to continue our blockade on d4.

If we don't play 12.Nf5 immediately Black can play 12...Re8 and give the bishop room for retreat on f8, or prevent Nf5 by playing 12...Qd7, so I suggest it's now or never.

On the site chessgames.com this position occurs 13 times, and in 12 cases White replied 12.Nf5. The other game continued 12.Qf3, which looks strange and unnatural to me, and Black won in 32 moves. Other possible reasonable-looking moves which spring to my mind, if we want to decline the exchange of our knight for Black's bishop, are 12.c3 and 12.Be3.

[gd_barnes]

O-O was a surprise response by Stockfish but it does get out of mainline books faster where Stockfish will have the advantage. I agree that Nf5 is the only reasonable response so that we can swap off our knight for black's bishop.

[LaurV]

Originally Posted by Brian-E

If we don't play 12.Nf5 immediately Black can play 12...Re8 and give the bishop room for retreat on f8, or prevent Nf5 by playing 12...Qd7, so I suggest it's now or never.

You are totally right about the exchange, although I don't see why is "now or never", but I think it is a good continuation for us, because then the next few moves are forced, Re8, NxB, RxN, f3, Nd6, Bg5, Re8, Re1, Rxe1, Qxe1 and we moved 6-7-8 moves toward those 34, and still stay strong on board!

All in all, we cornered him, told ya, he plays for draw now, haha.

[Brian-E]

Originally Posted by LaurV

You are totally right about the exchange, although I don't see why is "now or never", but I think it is a good continuation for us, because then the next few moves are forced, Re8, NxB, RxN, f3, Nd6, Bg5, Re8, Re1, Rxe1, Qxe1 and we moved 6-7-8 moves toward those 34, and still stay strong on board!

All in all, we cornered him, told ya, he plays for draw now, haha.

By "now or never" I just mean that we have the opportunity to force the exchange now, but if we do something else with our 12th move then Black can prevent it (12.Be3 Qd7 for example, or 12.Be3 Re8 13.Nf5 Bf8 or 12.f3 Nd6).

I agree with what both you and Gary further write.

[WMHalsdorf]

I would go with 12.Nf5 since it's would be what I would if I had only 10 seconds to decide and as well as if I had 10 minutes to decide.

The exchange of our knight for Black's bishop is tempting provided everything else remains equal. If Black improves tactically then the exchange may be considered an even trade.

Two questions: why would O-O be considered surprising? The possibility of this move has been assessed beforehand.

Second, how long did Stockfish take to make this choice. Was it a `real quickie` or a contemplated quickie? The time taken to deliberate over moves provides some information in terms of what may have been considered and why.

[Brian-E]

Originally Posted by jwaltos

The exchange of our knight for Black's bishop is tempting provided everything else remains equal. If Black improves tactically then the exchange may be considered an even trade.

Agreed. And there are also types of positions where a knight is better than a bishop in general, and aside from that there are positions where a particular bishop (either the light-squared or dark-squared) is particularly bad because the same side's pawns are mainly on the same colour squares restricting the bishop's movement and influence.

But we can say that the current position, with its open character, favours our dark squared bishop over the opponent's extra knight for the time being at least. For example, the opponent's rooks may end up vulnerable to attack by our long range bishop.

That perhaps partially answers your first question about why Stockfish's 11th move is surprising. Your second question, which interests me too, may need to be handled by MooMoo2.

[MooMoo2]

Originally Posted by jwaltos

Second, how long did Stockfish take to make this choice. Was it a `real quickie` or a contemplated quickie? The time taken to deliberate over moves provides some information in terms of what may have been considered and why.

I'll reveal more after the game is over, but for now, you can take a look at the attached screenshot. The bottom row tells the depth searched, the time spent on the move, the number of moves searched, and the search rate (number of moves per second).

The replies helped, thanks.
In my opinion, every piece off the board adds to Black's advantage due to its ability to increase its search depth which is one reason why I feel playing a full board is better against a computer. Surprise seems illogical within such a game of calculation. What would be the equivalent reaction of surprise for the computer..? I would prefer to dance around a little more on the board rather than settle for an immediate or obvious target.

Consider a long line of dominoes, an irrevocable sequence of events is set into motion when the first piece falls onto the second. Every piece will fall in a predetermined manner if everything is placed accurately leading to an inevitable outcome. Same thing here, how do we chum the waters appropriately to attract the fish without spooking it and set the hook without Stockfish feeling it. This is not a two-move discussion (contrary to what I waded into this thread with).

[Brian-E]

Originally Posted by jwaltos

[...]In my opinion, every piece off the board adds to Black's advantage due to its ability to increase its search depth which is one reason why I feel playing a full board is better against a computer.[...]

I don't feel qualified to comment on your remarks about "surprise" or the very philosophical discussion about prederminedness in the rest of your post, and maybe someone else will take that up instead, but I can't let the above quoted sentence pass without sticking my oar in again.

All practical experience of playing against programs has led to the opposite conclusion to what you write above. If there is one area where the best human players still stand a chance against computer programs, it is the technical type of position where calculation of precise move sequences is largely irrelevant. And, very roughly and with plenty of exceptions, the more pieces that are exchanged the more "technical" the play becomes and the less the program will be helped by its ability to examine millions of positions.

An important exception is when an endgame is reached with no more than 6 pieces/pawns - including the kings - on each side, or at a stretch 7. If the program has access to databases known in the trade as "table bases" then it will be able to play those positions perfectly, because they have been analysed exhaustively. But most endgames have more pieces on the board than that, and they mostly require good technique to play well, not calculation.