The dimmer dumb gambit against the French Defense

Intro

I just found out about this gambit today and I felt it was ridiculous how the computer voice was reading it as "dimmer dumb". Well, in a way it is. We are talking about a gambit that can be employed against the French Defense, but it can happen just as well from the Blackmar-Diemer gambit (yes, same Diemer) or even from the Queen's Gambit declined and, just like the O'Sullivan Gambit, needs to trap the opponent's bishop or go bust.

The Gambit

White plays e4 and Black responds with e6. Ugh! They want to play the French... White continues with d4, controlling the center, and Black goes d5, challenging. To which White plays c4, challenging the challenge. It's a stupid position, it looks silly, it gives Black -0.8 eval and their best move is the overwhelmingly played one: dxe4.

We could answer with the best move in the position: Nc3, and in that position Black plays Nf6 58% of the time. We could also answer with d5 directly, which I think it's more fun, but that's already -2 for Black. Either way, at some point the best move for White, according to Stockfish, will allow Black to castle, which is not what we want. In the position above, the move that wins 55% of the time for White is, you guessed it, d5!

Here are the moves so far: 1. e4 e6 2. d4 d5 3. c4 dxe4 4. d5 exd5 5. cxd5 Nf6 6. Nc3, with all but three moves being the most played. So the decision points are: e6 - Black needs to play the French, c4 and d5 - White needs to play the Diemer-Duhm. The rest are natural moves that lead to this:

White sacrificed a pawn and now Black is attacking the d-pawn with two pieces, while White is protecting it with two pieces. A natural move, made by 55% of people in this situation, is Bb4, pinning White's knight and renewing the threat. This is a blunder, though, because of Qa4+, which attacks the bishop, checks the Black king and the regular answer to this, Nc6, blocking the check and defending the bishop, fails to dxc6 !

That's it. People at every rating are falling into this head on. The win rate of the gambit is 49.4% for White to 46.2% for Black. In the critical position of the gambit it climbs to 58% / 38%.

And there are a lot of transpositions to a similar situation. Some might choose to not exchange the pawns and move the knight at move 4: 4...Nf6, which is the best move and brings the eval to -2. And we answer with 5. Nc3 and if they try to pin it, same thing. Black pushes f5 before Nf6, we pin their knight with Bg5, they pin our knight with Bb4, same thing. Black checks White's king directly with 5...Bb4, White blocks with Nc3, Black plays 6... Nf6, same thing.

It's like a curse: the position is so bad for White, but the first move, by far, that Black plays is always the worse.

Refutation

It's easy to refute this gambit, just don't hang your bishop :-) If instead of Bb4 something else is played, like Bd6 or Bc4 then castle, White plays Ne2, planning Ng3, some bishop move and castle and accepts playing with almost every chess metric on red and -1.7 eval. But if you're not at least two pawns behind in a gambit, you're doing it wrong.

Conclusion

A while ago I wrote about an "O'Sullivan system" which was pretty fun, also a one trick pony, also trying to lure the opponent's bishop into a trap. This is similar, but I feel it's even simpler and more likely to reach. The typical chess player falls for it every time! But that's statistics for you :)

This was a quick and dirty blog post, just to share my experience and because I've never even heard the name of this gambit before today. Don't expect a study and complex discussions about why this will certainly not get YOU, because you have the perfect French technique.

Have fun and let me know if you used this in your games!