A SICK OPENING VARIATION

In the Two Knights Defence, after the moves

1 e4 e5 2 Nf3 Nc6 3 Bc4 Nf6 4 d4 exd4 5 e5 d5 6 Bb5 Ne4 7 Nxd4 Bc5

the best move is 8 Be3, neutralizing Black's active bishop c5. 

The move 8 0-0 is also sound, defending the pawn f2 and providing White equality. 

In turn, the sharp move 8 Nxc6!?, ignoring Black's attack on f2, is generally considered invalid. However, my chess engine shows that the position is still equal. 

Two Knights Defence - 8 Nxc6!?

It is interesting to observe how chess theoreticians have described the move 8 Nxc6 leading to enormous complexities:

Playing devil's advocate...

    - Flear

8 Nxc6!? is obviously a critical response, but White comes under a dangerous attack. The position may be defensible but White should have both prior knowledge and iron nerves.

    - Pinsky

In principle no one in their right mind will go in for the variation 8 Nxc6...

    - Beliavsky & Mikhalchishin

Unfortunately, the variations provided by the theoreticians are so complex and lead to so non-standard positions that I cannot memorize them. It even seems to me that not only must White be sick when choosing such a sickening variation, but Black must be sick too, allowing to choose it.

For example, after the moves

8 Nxc6 Bxf2+ 9 Kf1 Qh4 10 Nd4+ c6 11 Nf3 Ng3+ 12 Kxf2 Ne4+ 13 Ke3 Qf2+ 14 Kd3 Bf5

 15 Nd4 Bg6 16 Rf1 Qxg2 17 Ke3 cxb5=/+

the following position is on the board:

Two Knights Defence - 17...cxb5

White's king is in the centre of the board. However, according to chess engines, and contrary to the statements of many theoreticians, Black, who has sacrificed a piece for two pawns, has merely a slight advantage.

From the databases, I found only two games with that position:

Nilsson - Bergstrom 2014

In that game, both sides made several mistakes in a tactical battle around White's king, stuck in the centre. 

In the game

Broszeit - Schleef 2020

White managed to quickly get rid of the central pawn e5, covering White's king, and Black got a mating attack.

Then, let Kasparov and Karpov play a hundred games from that position. 

I do not even remember how to arrive at it. And I do not understand it either. I have no idea of how to think in such positions. 

Is there any chess theory for handling such irregular positions? Are there any principles to follow? What is the cognitive value of playing such a position? 

Indeed, in the game 

Nikolaos - Alexandros, 2011

Black decided to avoid that position and forced a draw by repetition:

Nikolaos - Alexandros, 2011

In the present post, the Apronus chess software was used.

BLACK WON IN 23 MOVES - TWO KNIGHTS DEFENCE

In the Two Knights Defence, the variation 4 Ng5 is very sharp. White wins a pawn, but Black gets the initiative. The slightest mistake can cost a game for White.

I had black pieces in the game Krasotkin - Nanomaser on the platform ChessOK, 15 minutes per game. The game lasted only 23 moves.

Krasotkin - Nanomaster, ChessOK, 2024

You can analyze the game here:

Some comments on this game

Position after 10...Bd6

After 10...Bd6, 11 Nc4? was a mistake. White lost time to exchange one's centralized knight for Black's knight on the board's edge.

The correct moves were 11 d4 or 11 f4, defending the knight on e5. 

For example, after 11 d4 exd4 12 Nxd3, White's knight is close to White's king, while Black's knight is still on the edge. The disturbing central pawn on e4 has been exchanged. White's queen on d1 and bishop on c1 have gained some space.

The move 13 0-0?? was a final mistake. The correct move was 13 d4, after which White still has a bad position.

After 13 0-0??, Black has a winning combination. 

Position after 13 0-0

This combination is typical. First, Black sacrifices the bishop on h2: 13...Bxh2+. Then, Black plays 14...Ng4+. Then, depending on circumstances, Black plays 15...Qh4, 15...Qg5 or 15...Qd6.

Note that in the diagram above, White's queenside is entirely undeveloped. 

Worse, White's bishop on c4 also does not participate in the battle that will start around White's king. That bishop does not protect the crucial square g4 and, thus, does not deter the threatening move Nf6-g4.

With the move 12 Be2xc4, White's bishop abandoned the square e2 and landed on a seemingly more active position on c4. Unfortunately, the bishop on c4 alone does not threaten the well-defended pawn on f7.

White's position would be bad but much better than in the game if, on the diagram above, White's bishop would be on e2 instead of c4, as shown in the diagram below:

The position from above, if the bishop on c4 is on e2 instead

In the present post, the Apronus chess software was used.

BLACK WON IN THE TWO KNIGHTS DEFENCE

I had black pieces in the game on the platform ChessOK. Time control 15 minutes per game. The game

vugar79 - Nanomaster (0-1)

lasted only 17 moves:

vugar79 - Nanomaster, 2024

Some comments on this game

After the game move 9...Be6, the following theoretical position is on the board:

The game move 10 Neg5 grabs back the pawn, but it is a loss of time. 

Better is 10 Bg5, continuing the development and hindering Black from castling to the queenside. After 10...h6?, there is a tactical reply 11 Bf6!

After the game move 12...Bd6, the following position is on the board:

Black threatens with the combination 13...Bxh2+ 14. Nxh2 Qxd1. 

Unfortunately, White had to play 13 Qd3. 

After the game continuation 13 Bg5?, the following position is on the board:

White's bishop on g5 is hanging. The knight on f3 is overloaded. In the game Bohm - Reshevsky (Amsterdam 1977), Black used it to play 13...Bxh2+! 

However, when grabbing the pawn on e6, White managed to open the f-file for Black's rooks.

In the present game, and in the game De Abreu - Harshavardhan (Chess.com INT 2020), Black used the half-open f-file to attack with 13...Rdf8!

In the present post, the Apronus chess software was used.