Sunday, March 29, 2015

From the Miniature Reel (5)

From the Miniature Reel (5)

In the third round of the Aeroflot Open in Moscow, we saw something exciting coming out of an apparently mundane opening.

V.Zvjaginsev (2658) – B.Bok (2587) C44
Aeroflot Open (Moscow) (3), 29.03.2015
[Carsten Hansen]

1 e4 e5 2 Nf3 Nc6 3 g3 Bc5 4 Bg2 d6 5 0–0 f5
A sharp continuation that basically claims that White's play has been so harmless that Black can allow himself the freedom to attack without having completed his development or secured his king...Instead, the solid alternative is 5...Nf6 which promises more level-headed positions and about equal chances.
6 exf5 Bxf5 7 b4!?  

In order to take advantage of Black's king still being in the center and the kingside being weakened with 5...f5, White gives up a pawn to generate an initiative. My computer agrees with White's decision to sac the pawn in this fashion, somewhat in the style of the Evans Gambit.
The alternatives are:
7 Nc3 Nf6 8 Na4 Bb6 9 Nxb6 axb6 10 d4 0–0 11 c3 e4 12 Nh4 Be6 13 Bg5 d5 14 f3 exf3 15 Qxf3 Qd7, and the chances are about even, R.Lendwai-H.Baumgartner, Voitsberg 1995.
7 d3?! (This is entirely too tame) 7...Qd7 8 Nc3 0–0–0 (Black is unafraid) 9 Re1 a6 10 Be3 was V.Doronine-A.Danilov, Kimry 2008, and here Black should simply have played 10...Bxe3 11 Rxe3 Bg4 12 b4 Nf6 with a pleasant game.
7...Bxb4 8 d4
That is the idea behind the previous move, Black no longer controls the d4–square and White is trying to open things up.
8...Nge7 9 c3 Ba5 10 d5 Nb8 11 Qa4+ c6 12 Bg5 Bb6 13 Nh4
13 Nd4!? can also be considered; Black cannot allow himself to be careless, for instance: 13...Bd7 14 Qb3 Qc8 15 Nd2 cxd5 16 Bxd5 Nxd5 17 Ne4! 0–0 18 Qxd5+ Kh8 19 Nxd6 Qxc3 20 Nf7+ Rxf7 21 Qxf7 Qc8 22 Nb3 is a long line, but it is also relatively forced and looks promising for White.
13...0–0 14 Nxf5 Rxf5 15 Qh4!
Keep putting pressure on Black's tied up pieces.
15...Rf7 16 a4 h6 17 Bxe7 Qxe7 18 Qxe7 Rxe7
The queens have come off the table, but the pressure remains.
19 a5 Bd8?!
Black is trying to hang on to the pawn White so generously gave up on earlier. However, it may have been a safer policy to have handed back at this point after 19...Bc5 20 Nd2 Nd7 21 dxc6 bxc6 22 Bxc6, Black seems only marginally worse after 22...Rc8 23 Bb7 Rd8 24 Bd5+ Kh8 25 Ne4.
20 Nd2 Rc7 21 Nc4
White could also have considered 21 a6!?, e.g. 21...bxa6 22 Nc4 Be7 23 dxc6 Nxc6 24 Ne3 Rb8 25 Nd5 with a clear advantage, but the text move is  ultimately stronger, and as we will see in the game, also more effective.

Black continues as intended when he played 19...Bd8 a couple of moves ago, but how can White take advantage of his lead in development and generally much more active pieces?

21...Na6 22 Nxd6 Be7 is playable and safer.
22 Nb6!
Nunn's dictum: "LPDO - Loose pieces drop" off is a rule worth remembering. Black has an awful lot of loose pieces here.
22...axb6 23 axb6
Both black rooks are hanging...
23...Na6 24 dxc6 bxc6  

25 Rxa6!
Black may have hoped for  25 bxc7 Nxc7 26 Rxa8+ Nxa8 although this is lost too after 27 Bxc6. However, after the text move, it is curtains.

From the Miniature Reel (4)

From the Miniature Reel (4)

Having already lost a miniature in the first round, the last thing Savchenko needed in the 2nd round of the Aeroflot Open in Moscow. But things did not work out so well...

B.Savchenko (2581) – A.Predke (2530) E53
Aeroflot Open (Moscow) (2), 28.03.2015
Carsten Hansen

1 d4 Nf6 2 c4 e6 3 Nc3 Bb4 4 e3 0–0 5 Bd3 d5 6 Nf3 c5 7 a3 Bxc3+ 8 bxc3 dxc4 9 Bxc4 Qc7 10 Ba2 b5!?  

Black tries a move that has only been seen on one prior occasion.
The main line is 10...b6 11 0–0 Bb7 12 Re1 (or 12 Nd2 Nbd7 13 Bb2 Rad8 14 Re1 Ne4 15 Nxe4 Bxe4 16 c4 cxd4 17 exd4 Bg6 18 Qe2 Nf6, and White has a slightly better position, V.Tkachiev-R.Wojtaszek, Warsaw 2013) 12...Nbd7 13 Bb2 b5 14 c4 bxc4 15 Bxc4 Rab8 16 Qe2 Nb6 17 dxc5 Bxf3 18 Qxf3 Qxc5 19 Bf1 (While this may not look like anything amjor problematic for Black, White's pair of bishops guarantees him a solid advantage and White capably demonstrates that in the game) 19...e5 20 Rec1 Qe7 21 Qf5 Rfe8 22 Bb5 g6 23 Qg5 Nfd7 24 Qxe7 Rxe7 25 a4 a6 26 Bc6 Nf6 27 Ba3 Re6 28 Rab1 Nbd7 29 Rxb8+ Nxb8 30 Bb7 Nbd7 31 a5 e4 32 Bb2, and Black resigned, 1–0, A.Korobov-P.H.Nielsen, Eilat 2012.
Two other fully adequate alternatives are  10...Nc6; and 10...Nbd7
11 0–0 Bb7
In the only other encounter in this variation, Black continued with 11...Nbd7 12 a4 a6 13 c4?! (White is concerned to get stuck with passive position and wants to open the position up for his bishops, but this is not the way to go) 13...Bb7 14 h3 Rfd8 15 Qe2 cxd4 16 Nxd4 e5 17 Nf5 was played in K.Laciner-C.Ertan, Konya 2012, and now 17...b4!? leaves Black with a comfortable position.
12 Ng5?!
This looks quite artificial. The normal move is 12 Qe2 with fairly level chances.
12...Nbd7 13 f3 h6 14 Nh3 Bd5! 15 Bb1?!
I would probably have tried the more normal 15 Qe2, although Black has the more comfortable position after 15...a6. In the game, White tries to maintain the bishop pair.
15...Bc4! 16 Rf2 e5 17 e4 cxd4 18 cxd4 exd4 19 Qxd4 Rfd8 20 Bf4??  

How should Black continue?

White should have played 20 Bc2 (to keep d1 guarded) 20...Nc5 21 Bf4 Qb6 22 Qe3 Nd3 23 Qxb6 axb6 24 Rd2 Nxf4 25 Rxd8+ Rxd8 26 Nxf4 Rd2, and Black has a small but clear advantage in the endgame thanks to his active rook and bishop.
And White loses his queen on account of his weak back rank.


From the Miniature Reel (3)

From the Miniature Reel (3)

Another game from the first round of the Aeroflot Open in Moscow.

V.Potkin (2605) - M.Tabatabaei (2448) A29
Aeroflot Open (Moscow) (1), 27.03.2015
[Carsten Hansen]

1 c4 Nf6 2 Nc3 e5 3 Nf3 Nc6 4 g3 Bc5 5 Bg2 d6 6 0–0 a6 7 e3 0–0 8 b3 Ba7 9 Qc2 Re8 10 Bb2  

Black has a couple of alternatives at this juncture, but in all cases, White seems somewhat more comfortable: 
10...Bd7 11 Nh4 g5?! (11...Nb4 12 Qb1 Bc6 is worthy of consideration12 Nf5 Qc8 13 Ne4 Nxe4 14 Bxe4 Ne7 15 Nxe7+ Rxe7 16 f4 gxf4 17 gxf4 with a strong initiative and the clearly better chances for White, I.Nepomniachtchi-E.Najer, Moscow 2014.
10...Ne7!? 11 h3 (11 d4!? looks pleasant for White, whereas; 11 Nh4 Ng6 is fine for Black11...c6 (11...Bf5 12 d3 h6 is quite possibly fine for Black12 Rad1 Ng6 13 e4 Bd7 14 d4 Qc8 15 Kh2 b5 16 dxe5 dxe5 17 Nb1 h6 18 c5 Bb8 19 Nc3 Be6 20 Ne2 Rd8 21 Nc1 Rxd1 22 Rxd1 Bc7 23 Nd3 with the slightly better chances for White, M.Vachier Lagrave-M.Rodshtein, Caleta 2014.
11 Nh4! Bd7 
Or 11...Nb4 12 Qb1 Qe7?! (Black should possibly consider 12...a5 13 f4 c6 with a playable position, although White here too has the better chances13 a3 Nc6 14 Nd5 Nxd5 15 cxd5 Nb8 16 f4 Nd7 17 Nf5 Qf8 18 Qc2 Bb6 19 Rf2 f6 20 Raf1 e4 21 Bxe4 Rxe4 22 Qxe4 Nc5 23 Qc2 Qe8 24 Nh4, and Black is struggling an exchange now without sufficient compensation, I.Nepomniachtchi-J.Stocek, Porto Carras 2011.
12 a3 
12 Nd5!? is also worth a thought.
In a recent game, Black instead tried 12...Rb8, but this is not too promising either: 13 Nd5! Nxd5 (13...Nh7? is no good: 14 f4 exf4 15 Rxf4 Ne5  

was played in A.Rakhmanov-N.Nestorovic, Plovdiv 2012, where White now missed a winning continuation, can you do better than the 2600+ rated grandmaster behind the White pieces? 

16 Bxe5! dxe5 17 Rxf7!! Be6 (17...Kxf7 18 Qxh7 Qg5 19 Rf1+ Ke6 20 Nf5 is just devastating18 Rxc7 Bb6 19 Rxg7+ Kxg7 20 Qg6+ Kh8 21 Be4 Qd7 22 Qxh6 Qg7 23 Ng6+ Kg8 24 Nde7+ Rxe7 25 Nxe7+ Qxe7 26 Bxh7+ Qxh7 27 Qxe6+ Qf7 28 Qxb6, and White is up by a truckload of pawns, and will win easily.) 14 cxd5 Ne7 15 f4 f6 16 Rf2 a5 17 a4 b5 18 Bc3 b4 19 Bb2 Bc8 20 Qc4 Kh8 21 Raf1 (Things are already uncomfortably passive for Black) 21...Rb6 22 Rc1 Bb7? (22...Bb8 is very ugly, but unfortunately Black's best option23 Qxc7, and now it is just a matter of time when Black collapses: 23...Qa8 24 Qd7 Qd8 25 Rc7 Qxd7 26 Rxd7 Kg8 27 fxe5 dxe5 28 d6 Bxg2 29 Kxg2, and Black resigned, 1–0,0 S.Movsesian-S.Soors, Reykjavik 2015.
13 f4 Nd4 14 Qd3 
Since 14 exd4 exd4 15 Kh1 dxc3 16 Qxc3 c6 is fine for Black, 13...Nd4 looks like an attractive option, but he has not calculated the consequences of the alternatives carefully enough...
14...Nxb3 15 fxe5 Ng4? 
Black is concerned about potential sacrifices on f6, which is understandable, but now he ends up in even trouble. The best, according to the computer is 15...dxe5, e.g. 16 Nd5! Nc5 17 Nxf6+ gxf6 18 Qc2 Ba4 19 Qc3 with a clear advantage for White.
16 Nd5! 
The strongest move.
16...Nc5 Black of course cannot capture on a1: 16...Nxa1 17 Rxf7 Kxf7 18 Qg6+ Kf8 19 e6, and Black can only try to delay mate, but it is game over already.
17 Qc2 
It appears that  17 Qb1! is in fact the stronger move, as Black after the text move should play 17...Ba4. After 17 Qb1 that is not an option: 17...Be6 18 exd6 c6 19 Bd4 cxd5 20 cxd5 Bd7 21 Rxf7, and now 21...Kxf7 22 Qg6+ ends with mate on the next move.

White has sacrificed a pawn, in return he has very active pieces. How does the best take advantage of this situation?

18 Rxf7!! 
White could in fact even have considered this option on move 16: 16 Rxf7!? Nxe5 17 Nd5 Nd4 18 Rxg7+ Kxg7 19 Bxd4 Bxd4 20 Qxd4 c5 21 Qc3 with a very clear advantage for White, but I didn't want to spoil the tactical exercise after at this juncture.
18...Kxf7 19 Qh7! 
Removes the option of retreat to g8 and threatens a nasty check on f1 with sole not-yet-activated piece, the rook on a1.
19...Ke6 20 Nf5 Na4  

Now White can win in many ways, which one is the fastest way to mate?

21 Nxc7+ 
White mates the fastest with 21 Nf4+! exf4 (21...Kf7 22 Qxg7#) 22 Bd5#, but you can argue that the text move is the fastest way for White to win, because Black now resigned...

From the Miniature Reel (2)

From the Miniature Reel (2)

The latest edition of the very strong Aeroflot Open in Moscow has just started. In the first round, the top seed, Mamedyarov did bad things to his opponent...

S.Mamedyarov (2756) – B.Savchenko (2581) D37
Aeroflot Open (Moscow) (1) 27.03.2015
[Carsten Hansen]

1 d4 Nf6 2 c4 e6 3 Nc3 d5 4 Nf3 Be7 5 Bf4 0–0 6 e3 Nbd7 7 Qc2 c5 8 Rd1
White has several alternatives at this point including 8 0–0–0!? .
Black often plays 8...Qa5 at this juncture.
9 Rxd4 

A new move, but not a particularly good one. Black may have mixed a couple of lines up.
The main alternative available to Black is 9...Qa5 which is the main line, one recent game went: 10 Bg3 (or 10 Rd1 Nb6 11 Nd2 Bb4 12 a3 Bxc3 13 Qxc3 Qxc3 14 bxc3 Bd7 15 Be5 Ba4 16 Rb1 Nfd7 , and Black has already the better chances, A.Lenderman-S.Shankland, Saint Louis 2014) 10...Nb6 (Or 10...b5!? 11 cxb5 Bb7 12 Bd3 Nc5 13 0–0 , and a draw was agreed upon, ½–½, in E.Bacrot-L.Aronian, Porto Carras 2011, but there is obviously plenty left to play in this line, but Black has equalized) 11 Nd2 dxc4 12 Bxc4 Nxc4 13 Nxc4 Qa6 14 0–0 Rd8 (14...Bc5 15 Rh4 h6 16 Rd1 Bd7 , A.Goganov-E.Inarkiev, Jerusalem 2015, and now 17 Be5 Be7 18 Bd6 Bxd6 19 Rxd6 promises White the better chances going forward) 15 Rfd1 Rxd4 16 Rxd4 Bd7 17 Bd6 Bxd6 18 Nxd6 Bc6 19 e4 Qa5 20 Qd2 Qc7 21 e5 was seen in V.Potkin-D.Jakovenko, Yaroslavl RUS 2014, and now 21...Ne8 22 Nce4 Bxe4 23 Rxe4 Rd8 seems to equalize.
10 cxd5 Nxd5 11 Bd3 h6 12 0–0 Bxc3 13 bxc3 Nxf4 14 exf4 Qc7 15 Rd1 Nc5?? 

Rather surprisingly this move turns out to be the decisive error. Can you spot why and how White takes advantage of it? (Hint: It is not simple)

Black's best move is 15...e5 , e.g. 16 Rc4 Qa5 17 Ra4 Qc7 18 Nxe5 Nxe5 19 fxe5 Qxe5 20 Be4 , and White has no more than a lead in development and possibly a tiny amount of pressure against Black's queenside.
16 Bh7+! 
This is a very important point, the Black king has to be sent to h8.
16...Kh8 17 Ne5! 
This is the star move that point a firm finger at the sore spot in Black's position.
This looks dreadful, and it took awhile for me to realize why Black played this hideous move. Let's demonstrate what would happen if Black had no idea what is happening to him and what White is threatening: 17...b6 18 Rd8! (This is the threat, Black of course cannot capture on d8 twice because of Nxf7 mate) 18...Bb7 19 R8d7! Nxd7 20 Rxd7 Qc5 21 Rxb7 f5 22 Bg6 with a winning material advantage for White.
18 Bg6 gxf4 19 Qe2 
19 Rd8 is marginally better, but the text move secured resignation, so its effectiveness cannot be denied.

Saturday, March 7, 2015

My Books So Far

My Books So Far

Here is a little overview of which books I have written so far and which formats they are available in.
My first book was co-written by the Danish Grandmaster Peter Heine Nielsen, who is a very strong grandmaster (was at point rated with an Elo rating of 2700), but nowadays he is mostly written for being the the coach to World Champion Magnus Carlsen and previously the coach for then World Champion, Vishwanathan Anand.

The book is called: The Sicilian Accelerated Dragon – Improve Your Results with New Ideas in This Dynamic Opening

It has been out of print for a while, but is occasionally available on – usually at unreasonable high prices, but if you should find a cheap copy it is still a good book with the opening theory built into the notes of many main games. Some of the theory is outdated, and the analysis could do with a computer checking, but you will definitely learn a lot about the opening.

In the next book, I ventured out on my own. Like following books, it was published on the then recently started publishing company, Gambit Publications that was founded by Murray Chandler, John Nunn and Graham Burgess.
The book discussed the lines of the English Opening (1 c4) where Black responds with 1…e5.

It is called The Gambit Guide to the English Opening: 1…e5
First published in 1999 and later reprinted, it too is out of print, but available on and often also on, in both cases at reasonable prices.

That book was followed by another book on the English Opening, this time discussing the Symmetrical lines after 1 c4 c5.

  The Symmetrical English was published in 2001, and is also out of print, but more easily available than the previous two books. It is quite theory-heavy, but in many lines it was well-ahead of its time, introducing many new ideas, particularly in the so-called Anti-Indian lines.

With the English Opening covered reasonable well, I jumped to another favorite opening of mine, the Nimzo-Indian Defense, which arises after 1 d4 Nf6 2 c4 e6 3 Nc3 Bb4. In the book I “only” covered the lines starting with 4 e3, called the Rubinstein Complex. It has thus far been my most challenging and scientific work and possibly also the book I learned the most from writing. This is because the lines after 4 e3 are incredibly varied and occasionally very difficult to evaluate. Back then, my computer engine was completely unable to evaluate a number of lines correctly, in part because it had a hard time understanding the latent potential of White’s bishop pair, to name just one example.

The Nimzo-Indian: 4 e3 was published in 2002 and it too is very theory-heavy. The book ended up being 304 pages, but the original manuscript was at least another 60 pages. It is out-of-print, but is at present still available on

On suggestion from the publisher, I next tried my abilities as a writer on a much broader topic, that was not opening related. I choose to write on positional chess, a topic that is near and dear to my heart.

Improve Your Positional Chess is probably the book I have been proudest of and it received much praise in reviews, including by an authority such as American International Master John Watson. It is in own humble opinion a very good book on how to reach the right decisions and find the best moves and evaluate positions correctly in non-tactical positions. It is still widely available on-line and by chess retailers. This is so far the last book I have written for Gambit Publications.

This book was later translated into Spanish language:

Mejore Su Ajedrez Posicional was released by the Spanish publisher La Casa del Ajedrez in 2010 and is available on

My next book was an update of a repertoire book originally written by American International Master John Donaldson.

A Strategic Opening Repertoire was based on a repertoire put together by Donaldson in an earlier book. That book was long out of print, but presented a lot of ideas that were worth expanding on. This became my job, add additional and more recent games and dig a little deeper into the already presented material. While the book by no means is perfect it still fulfills its mission to present a number of opening ideas in the lines that White most likely will encounter after 1 Nf3 and 2 c4.
Recently I ran into a Fide master who says he still uses the repertoire outlined in the book, even if some of the lines realistically will not deliver much more than a draw against stronger players.
The book is available in both print and e-book format several places, including on

The next work, was another book for Russell Enterprises Inc. The publisher, Hanon Russell is also known as the man who created and founded for which I wrote the column Checkpoint from the February 2000 to September 2014. Hanon Russell sold the website a couple of years ago and it has since changed its original format.

Back to Basics: Openings covers nearly all openings in a light and educational fashion, designed to give the reader a look at each opening before deciding where to continue further opening studies. It is aimed at young or relatively recently started players, who has a rudimentary understanding of the game, but who wants to learn more. It too is widely available at chess retailers and at, at the latter in both printed and e-book (kindle) formats.

Next up, but not yet published are:

Back to Basics: Endings which originally was slotted for a 2010 publication, but due to work obligations from my day job has been delayed entirely too long, but now it looks like we are reaching something like a completed book.

A more recent project that will be out relatively soon, possibly in June 2015 on the English publisher Everyman Chess is

The Sicilian Dragon: Move by Move.

Finally, I should mention that in early 2003, I had an e-book released in a format that is no longer available under the auspices of It covered the Cambridge Springs Variation of the Queen’s Gambit Declined. I no longer have the notes or the files for it, so it may have been lost for all eternity.

That being said, look out for some new e-books that I will be releasing in collaboration with Russell Enterprises Inc. The books will exclusively be released in various electronic formats. The release dates are not yet available, but I will make sure to alert you when I have something more specific.

From the Mailbox

Recently I have received two new books from Russell Enterprises Inc.

DRAW! – The Art of the Half-Point in Chess

By Leonid Verkhovsky with Foreword by MIkhael Tal

It is available in both printed and e-book formats

My Best Games of Chess 1905-1954

By Savielly Tartakower with Foreword by Andy Soltis

It too is available in both printed and e-book formats.

I will revert with reviews of both books in the near future.

Friday, March 6, 2015

From the Miniature Reel

S.B.Hansen (2571) – J.V.Ferreira (2427) [D15]
16th Individual European Ch, Jerusalem (9), 05.03.2015
[Carsten Hansen]

1 Nf3 d5 2 d4 Nf6 3 c4 c6 4 e3 Bf5 5 Nc3 a6
This way of mixing the ...a6 system with the ...Bf5 set-up is not the best, although played on more than one occasion by Magnus Carlsen and other very strong grandmasters.
6 Bd2!?
6 Qb3 is a key alternative.
6...e6 is the key alternative, but White has also scored well in that line.
7 cxd5 cxd5 8 Ne5 e6 9 Qb3 Ra7 10 Rc1 Nbd7

What is White's most challenging move for Black to meet?

It should be said that Black's alternatives are not that good, e.g. 10...Bd6 11 Qa4+ Nc6 (11...Nbd7? 12 Nb5 wins for White) 12 Nxc6 bxc6 13 Qxc6+ is obviously better for White.
10...Be7 similarly runs into 11 Qa4+.
11 Bb5!?
This is clearly the most problematic move for Black to face. The alternatives are:
11 Nxd7 Nxd7 12 Ne2 (or 12 Na4 Be7 13 Bb4 0–0 14 Bxe7 Qxe7 15 Nb6 Nxb6 16 Qxb6 Raa8 17 Be2 , and a draw was already agreed upon, ½–½, Blagojevic-Ivanisevic, Budva 2003, but only Black can be better, e.g. 17...Rfc8 18 0–0 Bc2 and Black grabs hold of the initiative) 12 ..Nb8 13 Nf4 Bd6 14 Bb4 Bxb4+ 15 Qxb4 Nc6 16 Qc5 Ra8, and Black has equalized, Radjabov-Morozevich, Moscow 2002.
11 Na4 has also been tried: 11...Be7! is Black's best option, leaving White with at most a tiny edge after (11...Nxe5? loses on the spot: 12 dxe5 Nd7 13 Nb6! Nxb6 (or 13 ..Qxb6 14 Rc8+ Ke7 15 Bb4+, and it is game over for Black) 14 Ba5, and Black is completely toast in Kachiani Gersinska-Ionescu Brandis, Istanbul 2003) 12 Bd3 Bxd3 13 Nxd3 0–0 14 f3 b5 15 Nac5 Bd6 16 Bb4 Nb6 17 Ba5 Nfd7.
11 Qa4 is efficiently met by  11 ..Ra8! , and White has nothing.
11...Be7!? 12 Bxd7+ Nxd7 13 Nxd7 Qxd7 14 Na4 Qb5 (14 ..Bd8!? 15 Bb4 b6 has been suggested as playable for Black by Huebner, and that seems like a fair assumption, e.g. 16 0–0 f6 17 f3 Kf7 , and Black has solved his opening problems) 15 Nb6 Qxb3 (or 15 ..Bd8 16 Nc8 Qxb3 17 axb3 Ra8 18 Nd6+ Ke7 19 Nxb7 Bd3 20 Bb4+ Kf6 21 Nxd8 Rhxd8 22 Kd2 Bb5 is by no means easy for White to win, but Black is clearly on the defensive and will likely be so for many moves to come, Lekic-Mirzoev, Rethymno 2014) 16 axb3 a5 17 Nc8 Ra6 18 Nxe7 Kxe7 19 Rc7+ Kf6 20 Rxb7 a4 21 bxa4 Rxa4 22 Ke2± , and White obviously has all the chances of winning this endgame, although it by no means will be an easy task, N.Pert-Tippleston, Swansea 2006.;
11...axb5?? 12 Nxb5 obviously just loses for Black.
11...Qb8? 12 Bxd7+ Nxd7 13 Nxd7 (13 Qa4!? b5 14 Nxb5! axb5?! 15 Qxa7 Qxa7 16 Rc8+ Ke7 17 Nc6+ is an easy win for White) 13...Kxd7 14 Nxd5 b5 15 Ba5 Rb7 16 Nb4 Bxb4+ 17 Qxb4 Rc8 18 0–0 Rc4 19 Qd2, and with an extra pawn and safer king, White has a large advantage, which he eventually converted into a win, Ezat-Ranaivoharisoa, Tripoli 2009.
12 Bxd7+ Nxd7 13 Nxd7  

What is Black's best move?

This is not it! It looks like the natural move for Black, but it allows White time to give Black serious problems on the dark squares.
The answer is 13...Kxd7!, which you should not be ashamed if you missed. Even Magnus Carlsen has missed this move. White is still better, but only marginally so: 14 Na4 (Another approach is 14 Ne2 to make room for the bishop on b4, targeting the dark squares: 14...b5 15 0–0 Qb8 16 Ng3 Bg6 17 Bb4 Rc8 18 Bc5 Rac7 19 Bxd6 Kxd6 20 Qb4+ Kd7 21 Rc5 was played in Laurent-Berthelot, Guingamp 2004, and now Black should have considered the active 21...a5!? 22 Rxc7+ Rxc7 23 Qxa5 b4 24 Qa4+ Ke7, and Black should have sufficient compensation for the pawn) 14...b5 15 Nc5+ Ke7 16 f3 (16 a4?! Qb8 17 a5 Rc8 18 Bb4 Kf8 19 Kd2 Kg8 20 Nd3 Bxb4+ 21 Nxb4 Rxc1 22 Rxc1 Qxh2, and it is pretty clear that things have gone wrong for White, Vaganian-Frolov, Togliatti 2003) 16 ..Re8 (the text is logical, but 16...Kf8 may actually be better, e.g. 17 0–0 Kg8 followed by ...Kh7, and Black has equalized.) 17 e4 dxe4 (17...Bxc5? is a bad idea: 18 Rxc5 (in ChessBase Magazine, Huebner only gives 18 dxc5 dxe4 19 fxe4 Bxe4 20 c6 f5 21 Qg3 Kf7 22 c7 Qd7 23 Bf4 as risky for Black, but there are several improvements on this line, e.g. 19...Kf8! and 19 c6!?) ) 18 fxe4 Bg6 19 e5 (19 Qe3 Qa8 20 0–0 Bxc5 21 e5 Qe4 leads to equality according to Huebner) 19 ..Bxc5 20 Bb4 (20 dxc5?! Kf8! is actually pleasant for Black) 20 ..Kd7 21 Bxc5 (21 dxc5? Qh4+ 22 g3 Qe4+ 23 Kf2 Qd4+ is better for Black) 21 ..Qh4+ 22 g3 Qe4+ 23 Kf2 Qf5+ 24 Qf3 , and a draw was agreed upon in P.H.Nielsen-S.B.Hansen, Malmo 2003 - no wonder White in our main game was all locked in on the theory. But what would he have played against his own 13...Kxd7? That's an interesting question.
14 Na4! Bc7
The alternative is 14...0–0 15 Nb6, and now:

was Magnus Carlsen's less than fortunate choice: (15...Qb5 is possibly best, although 16 Qxb5 axb5 17 Nc8 obviously is not ideal for Black, but even so 17...Rxc8 18 Rxc8+ Kh7 19 Rd8 (19 a3 b4!) 19 ..Be7 20 Rd7 Rxa2 21 Ke2 Bf8 22 Rxf7 Kg8 23 Rxb7 Rxb2 will require some technique for White to win, but he nevertheless should) 16 Nc8! (16 0–0 a5! (16...Bc7 17 Ba5 Qd6 18 g3 leaves White with a pull) 17 Nc8 Ra8 18 Nxd6 Qxd6 White's advantage disappears 19 Qb5 Qa6 20 Qxa6 Rxa6 21 Rc7 Rb6 22 Bc3 a4 with no more than a small plus for White.) 16...Qxc8 (or 16...Ra8 17 Nxd6 Qxd6 18 Bb4, and White wins) 17 Rxc8 Rxc8 18 Qb6! (As indicated by Rogozenco, it is less accurate for White to play 18 0–0 Rc6 19 Rc1 Rxc1+ 20 Bxc1 b5 "allowing Black to activate the pieces and reach a perfectly playable position", but 19 Bc3 followed by a2–a3 and f2–f3 is certainly more challenging) 18...Bb8 19 0–0 Kh7 20 Rc1!, and White is winning, Ponomariov-Carlsen, Wijk aan Zee 2007.
14...b5? 15 Nb6 loses on the spot.
14...Qd8 15 Bb4 (15 Nb6 Bc7 16 Qa4+ transposes to our main game) 15 ..0–0 16 Bxd6 Qxd6 17 Qb6 Qxb6 18 Nxb6 a5 19 Rc7 left Black with a very uncomfortable ending which White eventually won, Mchedlishvili-Raznikov,  Warsaw 2013.
15 Nb6 Qd8 16 Qa4+ Kf8?

What is White's strongest move?

As indicated by Rogozenco in ChessBase Magazine, Black's best is 16...Ke7 17 Ba5 Bxb6 18 Qb4+ Qd6 19 Qxb6 Qxb6 20 Bxb6 Raa8 21 Rc7+ Kf6 22 Kd2 with a difficult endgame for Black. White obviously has control over the c-file, has a rook nicely situated on the 7th rank as well as having relatively easy access to the queenside with his king. Black on the other side has a remarkably ineffective king and bishop. A possible continuation is 22...Rhc8 (the exchange of a pari of rooks will likely help Black's defensive task in contrast to allowing White to play Rhc1, Rd7 followed by Rcc7) 23 Rhc1 Rxc7 24 Rxc7 Rb8 25 b4 (White should not let himself get tempted to win a pawn with 25 Ba7 because of 25 ..Re8! 26 Rxb7 Re7, and all of a sudden Black has a pure opposite-colored bishop endgame that he should be able to defend) 25...g5 26 a4 h5, and now: 27 Kc3 appears to be the only chance to win: (27 a5 g4 28 b5 axb5 29 Ba7 (29 Kc3!? b4+ 30 Kxb4 Bd3 31 Ba7 Re8 32 Rxb7 Re7 33 Rxe7 Kxe7 34 Kc5 Kd7 35 Kb6 Kc8 36 g3 Bc2 37 a6 Bd1 38 Ka5 Be2 , and White will not get anywhere) 29...Ra8! (Now, on the other hand, Black can no longer use the drawing method from before: 29...Re8? 30 Rxb7 Re7 31 a6 , and White wins) 30 Rxb7 b4 31 Bb6 Be4 32 g3 Kg6 33 Bc7 Ra6 , and White still has some work to do if he is to win at all) However, 27...e5!? (27...g4 28 g3 Be4 29 b5 axb5 30 axb5 wins for White; 27...Be4 28 f3 Bf5 29 b5 axb5 30 axb5 Ra8 31 Rxb7 (Rogozenco) and White is winning.) 28 Kb3 exd4 29 Bxd4+ Ke6 30 Ba7 Rd8 31 Rxb7 d4 32 Bxd4 Be4 33 Rc7 Bxg2 34 b5 axb5 35 axb5 with some winning chances for White.
17 Qd7! Qxd7 18 Nxd7+ Ke7 19 Rxc7 Kd6 20 Ba5
And with everything guarded, there is nothing left for Black but to resign.