I put some work into maintaining this blog, but I never could do it without the ideas, analysis and games that Readers send me.
For example, here is an introduction and then some analysis that I recently received (thank you, Anastazja) concerning a chess game where Stockfish gave Fruit 1.2 "Jerome Gambit odds".
Interested in the Jerome Gambit, I decided to look into it a little bit. However since my own chess playing abilities are a little weak, and since I don't play chess myself and I am more interested in AI research (and that of course leads to chess), I decided to test it on some computer games. However, since the Jerome Gambit is a very hard line to hold as white, I needed to change things a little bit. Considering that you would usually play Jerome Gambit against unprepared opponents looking to surprise them, it in theory has no place in today's computer chess. Their deep search can easily spot tactics and not fall victim to early queen attacks. However it turns out, that if you look deep enough, even computers can be outplayed with the opening. In the game I wish to share, white managed to use the queen checks to create a blocked position with very long term plans, making it very easy for opponents to become overzealous.
Since the evaluation of the top chess engine Stockfish is at -3.5 pawns black advantage and the same engine can't surprise itself, I decided to try something different. I put Stockfish as white and an old engine called "Fruit 2.1" as black. Fruit is an old engine, however it still is about 2800 elo in strength, which would put it near world champion level. Moreover, its strength mostly comes from tactical prowess, as engines back in the day were relatively weak positionally. One would think that the Jerome Gambit is a tactical line that looks for compensation in terms of attack on the king that is in the open, so an engine with superhuman tactics should easily hold it. It turns out that it's not so simple.
The game is 150 moves long, however most of those moves are just "shuffling" moves waiting for 50 move rule to take effect. White of course wants the draw, as it's a piece down, however black doesn't want that to happen. Even though most of the game are "pointless" rook and king moves, the critical moments of the game are definitely very interesting in my opinion.
Game starts in the Jerome Gambit Accepted position, after Kxf7. White develops its remaining pieces. This, combined with queen checks, has led black to a little chaos. Black tried to force the queen trade, however the little positional and development edges white gained earlier made it not so simple. When black finally got its pieces developed and queens off the board, the position was already blocked and white got its own fortress ready.
After creating a blocked position, both engines just shuffled around for multiple moves. The "shuffling" starts at move 34.Rf2 and continues for about 100 moves. White, being a piece down, has held the position because black could make no progress. Black constantly looked for opportunities, however the preparation in the first 30 moves of the game has made it impossible for black to find any kind of an attack.
First 50 move rule reset happens at [71]...axb4 and [72].axb4. This pawn exchange doesn't open the position however, so engines continue to shuffle around. It's on move [121]...Rxc6 that the game gains a new life. Fruit playing as black, sacrifices the rook for a knight to open up the position hoping for some kind of an attack. Black is still up in terms of pieces, bishop and a knight for a rook. White has one pawn more, however in engine games pieces are usually worth a lot more than pawns. It turned out to be a very serious mistake. White managed to showcase a beautiful temporary rook sacrifice that led to a creation of connected passed pawns which ultimately gave white the material back and ultimately won the game.
This result surprised me. If a 2800 elo engine has fallen victim to impatience and being overzealous because of the material advantage, a human surely can too. I'm not an expert so I can't really evaluate the position after it got locked and I don't know how it would play out if it was two humans, however I can easily see humans sacrificing and going for even worse attacks way earlier. The mental advantage Jerome Gambit can definitely catch some humans off guard, however I would never it would happen to an engine as well.
