The result suggests the following interesting question: Which attempts on White's part to answer Black's Queen side attack make the advance ...f5 more favourable for Black?

<haydn20: 16 b3 seems to invite ...f5. Maybe stirring things up on the K-side with e.g. 16 Ng5 is better? It seems to me that in this tournament Carlsen punished every minor positional mistake severely: "Tactics flow from a superior position.">

This suggests the question: Why does 16 b3 invite ...f5?

One answer is that 16 b3 removes an obstruction to Black's King's Bishop on the long diagonal and so gets pinned the N on c3 which defends the e4 pawn which gets attacked by ...f5.

There is also another thing. If White can't respond to ...f5 with e5, that makes the e4 pawn immobile, and according to Lasker, that which is immobile suffers violence.

Firstly, The move 10...a6 is passive and accepts that Black's Queen side pawn majority is going to be a target instead of a weapon. It makes it more difficult for Black to organize the pawn advances ...b6 and ...c5.

More importantly than that, it was the dark squared bishops which were exchanged in the present game, instead of the white squared bishops as in the fourth game of the match.

If in the position after 10 b4 we replace the white squares bishops in this position with dark squared bishops, as in the fourth game of the match, we can see that it is easier for Black to play the pawn advances ...a5 and ...c5, as well as to attack White's King side.

The move 36 Rg7+ suggests one reason why. On 36...Rxg7 37 fxg7+ Kxg7 38 Bh6+ wins the exchange.

If in the position after 36 Rg7+ we remove from the board the Rooks on f8 and h1, on 36...Rxg7 37 hxg7 does not come with check, and on 37...Kxg7 White does not have the resource of Bh6+.

The answer is that White does not need to prevent it because with the best play Black's centre is going to become a target instead of a weapon.

If the reason for this is that after 30 Bxf5 Qxf5 Black's Queen occupies the b1-h7 diagonal, this suggests refraining from making that concession by 30 Qc2.

However against the move 30 Qc2 Petrosian may have had prepared the following combination: 30 Qc2 Qxe3!! displaces the f2 pawn which defends the fork ...Nxe3 forking White's King on f1 and Queen on c2.

On 31 fxe3 Nxe3+ 32 Ke2 Nxc2 makes a X-ray capture, Black's Queen's Bishop attacking White's Queen right through White's Kiong's Bishop.

On 33 Bxc2 Bxc2 attacks the N on b3 which defends the White Rook on a1.

On 34 Nd2 the White Rook on a1 is undefended and so the White N on a2 is pinned to White's Rook on a1 and so cannot defend the b4 pawn and so allows 34...Bxb4

On 31 Bxf5 Qxb3! both draws White's Queen on to the square b3 which can be forked by a N on d2 and removes the N on b3 which covers the d2 square.

On 32 Qxb3 Nxd2+ 33 Ke1 Nxb3 displaces the White Rook from its defence of the N on a2 and on 34 Rb1 Rxa2 35 Rxb3 Black has regained the piece and with interest.

However this does not by itself explain why White loses the game.

If we take a look at the course of the rest of the game, we may be able to observe that Black's King invades White's King side, marching to the square f3. To do this the black king makes use of the white squares which are not defended by White's remaining bishop.

White could try to prevent this by placing the King side pawns on white squares instead, but then they might become targets for Black's Queen's Bishop.

White has been given therefore an unwelcome choice. He can either expose his King pawns to Black's QB by placing them on the white squares, or else he can place them on black squares and expose the white squares to invasion by Black's King.

Perhaps White thinks that when he attacks on the Queen side with his Rook the exchange Rxh8 will serve to draw Black's Rook away from the Queen side.

It is not obvious at move 17 why this view is mistaken.

In the event of h4 and g4- as played in the game - Black will want to move his N on f6 and play then ...f5. However the move ...Ne8 can be answered by Be7 trapping the Rook on f8.

In that case Black will want his Queen on e8. However then d7 is the only square left for the N.

Therefore Black has to keep the square d7 free for the KN, but 11...Nf6-d7 invites the attack 12 Nb5.

Moving the King to h8 and freeing the square g8 for the KN as in the game does not work because White plays h4 and h5 before Black can play ...Ng8. On 14 h5 Ng8 15 hxg6 the h7 pawn is pinned and cannot recapture on g6.

All this suggests that instead of 10...Nc5, 10...Ne8 is better.

However this is not the end of the story, for Black has at least one alternative left still.

Instead of 11...Bd7 Black can play the eccentric looking 11...Qd7!! obstructing his own QB, as Nimzovich did in the famous game P F Johner vs Nimzowitsch, 1926

The move 11...Qd7! both unpins the N on f6 and defends the c7 pawn on the event of Nb5, and now the advance ...f5 becomes possible.

Here it is (in german)
Through extra conditions Alekhine excluded Capablanca from tournaments in Bled and San Remo. Also, Spielmann mentions Nimzowitsch who was not invited to London and Bern.

Here is the letter:

<Sehr geehrter Herr Weltmeister Dr. Aljechin! Sie werden wohl staunen, Herr Weltmeister, über meine Unverfrorenheit, die selbst vor den Stufen des erhabenen Weltmeisterthrons kein Halt kennt. Aber ich klage an! Natürlich nicht Ihr geniales Spiel, für das ich als Schachenthusiast nur Hochachtung und Bewunderung übrig habe. Nein, meine Klage gilt nicht dem Weltmeister Dr. Aljechin, sondern dem Kollegen Dr. Aljechin...Sie haben in San Remo 1930 und Bad Bled 1931 neben dem Extrahonorar noch besondere Bedingungen gestellt und dadurch Capablanca von diesen Turnieren praktisch ausgeschaltet. Natürlich haben Sie Capablanca nicht direkt abgelehnt, sondern einen viel versteckteren Weg gewählt, der aber nichts an den Sachverhalt ändert, den ich als Branchenkundiger wohl zu durchschauen vermag. Muß denn Capablanca für seinen überlegenen Sieg in New York 1927 so arg büßen? Aber lassen wir die Vergangenheit begraben sein und befassen uns lieber mit Ihrem Kollegen Nimzowitsch, der doch nach Ihnen und Capablanca der erfolgreichste Meister der Gegenwart sein dürfte. Scheint es nicht auffallend, daß er weder nach London 1932 noch jetzt nach Bern eine Einladung erhalten hat? Mindestens wäre es für Sie leicht gewesen, eine Einladung an Nimzowitsch durchzusetzen. Als Dr.jur. wird Ihnen der "dolus eventualis" (bewußte Fahrlässigkeit, d.A.) bekannt sein... Mein lieber Weltmeister, verdreschen Sie weiter Ihre Gegner, möge Ihnen zum Entzücken der ganzen Schachwelt noch viele Großtaten gelingen, nur gewöhnen Sie sich das Kommandieren ab, sonst müßte ich Ihnen das bibliche Wort des Propheten Hosea, frei nach Marco zurufen: Wind säet er, und Sturm wird er ernten. Das Maß ist voll, jenseits und diesseits des Ozeans mehren sich die Stimmen, die sich gegen die Diktatur des Weltmeisters auflehnen.>

Thank you for the letter.I do not speak German, but here is the google translation:

If so, Anand pre-empts all that by the pawn sacrifice 15...d5!! To begin with, White's N on c3 is overworked. If takes the d5 pawn it cannot then defend the e4 pawn. On 16 exd5 Bb4 17 d6 Qd7 ( Black can't allow 18 d7 and 19 d7-d8/Q) the d6 pawn is going to fall.

It may take no more than a few tiny adjustments to Black's play to transform the evaluation of the position from a one sided looking win for White into little or no advantage for White.

After the move 13 Nh4 it is true that it seems much easier for White to play the pawn advance f2-f4 than it seems easy for Black to play the pawn advance ...f7-f5.

This is because it is much easier for White to free his f2 pawn by playing the move Nh4 than it is easy for Black to free the f7 pawn to move by playing the move ...Nh5.

However can Black do nothing else that is useful with his king's knight?

One answer is that the N on f6 supports the counter-advance 13...d5! If Black can play safely this advance this may defuse any prospects for a successful White king side attack arising out of the pawn advance f2-f4.

It is understandable that with Black deprived of counterplay and backward in development Kramnik should have wanted to attack quickly by c5.

However Black has not only been deprived of counterplay on the King side, White has in fact taken the initiaive there from Black, so that White has the initiative on both wings.

Now on either wing, the greater the advantage which White has over Black there, the better the chances of success are for his attack

White can muster in fact a greater superiority of material force over Black on the King side than he can arrange on the Queen side.

Therefore it is on the King side that White must proceed energetically and on the Queen side where he must play more conservatively.

Therefore 18 c5? followed the wrong policy. On the Queen side it was better to play more cautiously and to attack the King side instead.

So I thought before.

However the analysis given by <Hesam7> suggests another possibility.

What if the Queen side attack c5 assists White's King side attack instead of diverting resources away from it?

If the analysis given by <Hesam7> is right, this suggests that Kramnik's mistake was not 18 c5 but 20 Qh5 instead of 20 Qg4 and for this reason: Because it is after 20 Qg4 that White's Queen side attack is able to assist properly White's King side attack.

It is after the move 20 Qg4 that White's Queen side attack which includes moves such c5 and Rb1 followed by the sacrifice Rxb7! is able to act properly in concert with White's King side attack which includes moves such as fxg6.

In other words, it is the choice of the move 20 Qg4 instead of 20 Qh5 which enables White's Queen side attack to cooperate properly with White's King side attack.

1. Black's Rook on e8 is potentially overworked. If it has go to to g8 in reply to Rg4 it cannot then tie White's Queen's Rook to the defence of the e4 pawn so that this Rook becomes free to go to d1 to attack Black's d6 pawn.

On the chessdom website GM Naiditsch says of the position after Carlsen has set up a pawn centre that Aronian has no counterplay at all.

This gives us an indication of the explanation for Aronian's defeat.

After White has set up his pawn centre, Aronian has, by playing the flank pawn advances ...h5 and ...a5, made it more difficult for Black to play the pawn advances ...f7-f5 or ...c7-c5 so as to attack White's centre.

Another thing is that after 15 e4 the move 15...dxe4 concedes the centre and an advantage in space to White. It is a suboptimal move according to the chessdom analysis. An alternative to 15...dxe4 is to try to hold on to the centre by eg 15...Nb6.

On the move 19 gxh5 to quote from his remarks < 19 gxh5? Correct is 19 Ba2 and Black has to play very precisely to keep out of trouble...>

Reshevsky's comment on the move 22...Ne5 is < By giving up a pawn, Black has the initiative. The two bishops and the exposed position of the White King are more than sufficient compensation for the pawn sacrificed>

This suggests the following question: Why does White's acceptance of the pawn transfer the initiative to Black?

If we look at the position after the move 22...Ne5 we can see that Black has removed White's king's bishop so that it no longer controls the square g8.

Black's King enjoys therefore the use of the square g8 as a flight square, so that the check Qh4+ is no longer much of a threat.

With White's KB controlling the square g8, the move Qh4+ would indeed be a threat.