Gambits declined gone wrong

When declining a gambit it's important to decline with the best move. In this example, White declines with a blunder and is soon trapped in a fork. Several moves later White is trapped in a double attack and is soon mated. Black wins with an accuracy of 95.

#1
"decline with the best move" ++ It is always desired to play good moves

"White declines with a blunder and is soon trapped in a fork." ++ White apparently did not think before playing 4 Nc3, else white would have calculated what to do after 4...fxe4 5 Nxe4 d5.

It is a common mistake to play the opening too fast.

It's easy to blunder into a fork. In this instance, White had just two options to defend e4: d3 or Nc3. Nc3 seems like a good development move. This is why it's important to study gambits which occur in the opening phase of a game and to choose whether to accept or decline. If declining, not to get into trouble with a poor declining move. The best declining move here is not 4. d3 but actually 4. d4 which will result in an equal exchange of pawns.

Although White declines the gambit with a better defending move, followed by a fork of Black's Queen and Rook, Black's Queen counterattack is not handled well. Eventually, the Queen's are exchanged leaving Black with better development in the centre that leads to a promotion and mate. Black wins with an accuracy of 97.2.

#4
5 Ng5 violates the opening principle not to play the same piece twice.
Just developing 5 Nc3 or 5 O-O is much better.
6 Nf7 just invites 6...Qh4. The threat 7 Nf7 is stronger than its execution 6 Nf7. 6 h4 prevents 6...Qh4
8 Nxf8 just invites 8...Ng4. 8 Nd2 intending to defend with 8 Nf3 was still equal.

Agree with that principle of continue development rather than early attacks.

The Rousseau gambit has gone to the wastebin (excluding blitz and bullet games) because of the powerful 4.d4! - which is much more effective than the analogous Jaenisch gambit line, where Black will survive because the bishop is vulnerable at b5 and Black can get things straight by attacking it (1.e4 e5 2.Nf3 Nc6 3.Bb5 f5 4.d4 fxe4! 5.Nxe5 Nxe5 6.dxe5 c6! - threatening ...Qa5+ and ...Qxe5, when white is practically forced to make an obscure piece sacrifice with 7.Nc3).

On the Rousseau, neither 4...fxe4 5.Nxe5 d5 6.Bb5 Qd6 7.c4!, nor 4...exd4 5.e5! work- especially on the second line Black can barely find a decent move already.

It's like white is refuting the gambit with something-like-a-countergambit (although this is closer to a positional massacre than a countergambit).

With all of these unsound gambits, how playable it is depends partly on the time control and especially on who your opponent is and what their rating is. Most players below something like 1500 level are not going to be familiar with any of the rarely played gambits and will fall into one of the many traps.

However when you play stronger players they will either know or be able to calculate all the lines better than you and the gambit will not work.

I agree that gambits won't trouble experienced players. But, they can trouble beginners who don't follow the principles of sound play. I'm posting them here to demonstrate to beginners why they need to respond to gambits with sound principles to avoid the traps.

Congratulations White, you eventually found the strongest declining move 4. d4. After 4. ...exd4 White plays another good move 5. Nxd4 followed by Black's 5. ...Nf6 (preventing the White Queen from h5+). But, White's mistake 6. Nxf5 allows a series of strong moves by Black which leads to an exchange of Queens and a check with tempo. White's King blunders by moving to an empty file and is checked again by Black's Rook. White cannot mount a counter-attack and is eventually mated after Black regains a Queen from a promotion. Black wins with an accuracy of 99.1.

Either you missed, or you pretended missing the suggestion 4...exd4 5.e5!, and posted a silly line instead.

This is very typical, and works in quite a few openings:

- The Jaenisch, 1.e4 e5 2.Nf3 Nc6 3.Bb5 f5 4.d4 exd4? 5.e5!

- TheClassical Ruy, 1.e4 e5 2.Nf3 Nc6 3.Bb5 Bc5 4.c3 f5 5.d4 exd4? 6.e5!

In all 3 cases Black is in deep trouble.

You are either needing a new pair of eyglasses, or a better guide at trolling- maybe both.

#11
5 Nxd4 Nf6 6 Nc3 should still win for white.

This is "just" better for white.

Why allowing Black the luxury of ...Nf6, and not playing 5.e5! instead?

This series of posts is showing the result of poor choice moves when presented with a gambit. When presented with a gambit there are traps whether White accepts or declines the gambit. It's up to beginners to learn why 5. e5 is a better move than 5. Nxd4.

Thankyou, I'll look at the Jaenisch next.

I'm deliberately posting poor choice moves actually played by low rated players playing White. So that beginners can find better moves when presented with gambits.

The right move for Black in both the Jaenisch and the Classical Ruy/ Cordel Gambit is taking at e4, not d4.  In the Rousseau... both captures (at d4, or e4) are bad.

If you want to play the Jaenish in enterprising fashion (because it can also be played solidly) I recommend Jonathan Tait's book "A Disreputable Opening repertoire" which came out recently.

In the Latvian Gambit, Black offers f5 in move 2 which White declines with Nc3 rather than the passive d3. Black trades pawns and attacks the White Knights. White activates the Queen early and Black's Kingside pawn structure is decimated. However, this leaves plenty of room to develop the back rank pieces while White's pieces are trapped behind a wall of pawns. During the ensuing battle the Queens are traded and Black's g pawn makes it to the other end. Black promotes first and wins the game with an accuracy of 93.5.

Still with the Latvian Gambit, what happens if White tries to keep its Knights? So, rather than 5. Nxe5, it becomes 5. Ng3 with the Knight moving to safety. Black still ends up with a strong centre and clear room for better development. Black wins again with an accuracy of 96.1.

Your line is flawed from the start.

After 3.Nc3 fxe4 white could (and should) play 4.Nxe5, not 4.Nxe4. Black is already at a difficult situation, and his best chance is to lose "just" one pawn after 4...Nf6 5.Ng4 

"...which White declines with Nc3 rather than the passive d3. Black trades pawns and attacks the White Knights" is just another hope chess statement.