Why is there a completely losing move in my engine's opening book?

After 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3 Bf5 6. Ne5 Nbd7
(Slav Defense - Chameleon/Chebanenko Variation)
My engine's opening book continues with the losing 7. g4??
And then it continues with the variation 7... Nxe5 8. dxe5 Nxg4 9. cxd5 Nxe5?!

I've made Houdini 3 Pro evaluate the position, and indead 7. g4?? is completely losing.
Houdini suggests 9... cxd5! instead of 9... Nxe5?!, with an evaluation of -0.85
But even after the slightly innacurate 9... Nxe5?! Houdini still evaluates the position as -0.40
While if White played the correct 7. Qb3 the evalution would have been +0.21

I've only made it evaluate the position for 15 minutes, so maybe there's some deep hidden secrets in the move 7. g4, but it looks very unlikely...

I've looked in a game explorer, and I found one game which started with 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3 Bf5 6. Ne5 Nbd7 7. g4??
And that game was between no other then Super-GM Peter Leko against World Champion Magnus Carlsen (in Monte Carlo in 2007).
Houdini said that game was full of blunders. Carlsen missed a lot of knockout moves, Houdini even gave an evaluation of -17.97 in the middle of the game, but it ended in a draw...

Originally posted by Marc Benford
After 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 a6 5. e3 Bf5 6. Ne5 Nbd7
(Slav Defense - Chameleon/Chebanenko Variation)
My engine's opening book continues with the losing 7. g4??
And then it continues with the variation 7... Nxe5 8. dxe5 Nxg4 9. cxd5 Nxe5?!

I've made Houdini 3 Pro evaluate the position, and indead 7. g4?? is completely losing.
Houdin ...[text shortened]... utes, so maybe there's some deep hidden secrets in the move 7. g4, but it looks very unlikely...

It was one of several moves put in by Games Moderators to identify internet cheats. See how deep the counter conspiracy goes - employing Leko and Carlsen - or were they just innocent bystanders...?

I've seen engines evaluate completely drawn positions at plus or minus two pawns so I wouldn't put too much stock in an evaluation on move 7.

Why don't you figure out the ideas behind g4 and decide if they are good or bad for yourself? Maybe play some games with it if you don't fully understand tat first.

Ragwort is correct.

The makers are fed up with people using their kit to cheat at net chess so
they loaded in a few moves giving false evaluations to trip them up.
I thought everyone knew this.

I was watching a marathon on tv the other day and even the winner took over 2 hours to finish.

This just seemed wrong to me so I loaded up my car and sure enough it took me only about half an hour to travel 26 miles, and that was with stopping for a coffee.

Hi hedonist

The marathon is for people without cars.
I thought everyone knew this.

Looks like he only sign up just to talk on the forums. Even though he joined in May, he has yet to make a single move.

I have received a PM asking me to explain my earlier post in this thread. Let's see if this helps to bridge the sar chasm.

Scenario:

You are playing a game of chess on the internet. Against your a6 Slav White plays 7. g4. What is the likelihood your opponent is blindly following the Houdini opening book?

Scenario:

As White you try 7.g4 against the a6 Slav. Black plays 9....cxd5. What is the likelihood they are blindly following Houdini's analysis?

Finally this quote from Fischer's 60 memorable:

"When I told Bronstein at Mar del Plata 1960 that the text was a tremendous improvement over his game with Reshevsky, he replied: "Of course. After seven years one must find an improvement."

Ragwort,
Were you trying to be clear that you were really being sarcastic instead of serious about Carlsen and the other chess player? Couldn't Carlsen or whoever else have played Houdini or another chess program for preperation with Houdini or another program playing g4? Thus, possibly resulting in a g4 move for the human chess player in an OTB encounter.

Furthermore, they tried to investigate "Ivanov," if I am correct, for possible cheating in an OTB game. He apparently left the scene without the investigators finding proof.

Originally posted by KingOnPoint
Ragwort,
Were you trying to be clear that you were really being sarcastic instead of serious about Carlsen and the other chess player? Couldn't Carlsen or whoever else have played Houdini or another chess program for preperation with Houdini or another program playing g4? Thus, possibly resulting in a g4 move for the human chess player in an OTB ...[text shortened]... cheating in an OTB game. He apparently left the scene without the investigators finding proof.

Irony and sarcasm are devices that may not cross cultures or language barriers particularly well. It can also be difficult for some people to appreciate, those who think more literally than others or some on the autistic spectrum for example.

Benford asked why there was a completely losing move in his engine's opening book. To me this question would be better addressed to the programme's compilers rather than RHP but, since he expected an answer, I gave him one.

In years gone by, mistakes in printed literature might be pointed out by the readership to the publishers. Even in chess opening literature this was the case, although there was sometimes the suspicion that the author might keep some things back, especially if they were an active GM. In addition, if you find a mistake in the work, why not keep it to yourself for use in a game.
That is how chess opening theory often works at competitive level in both OTB and CC. To me Benford's question appeared to ignore all these factors with the assumption that Houdini is somehow utterly infallible, or that he had paid money for something that was fallible. Not for nothing did Nimzovitch say "Theory is a short sighted lady".

The irony seizes on that assumption by creating a scenario that Houdini's manufacturer's deliberately put a duff opening move into their opening book
(rather than copying some GM game without question) to catch out those that follow their engine's book without question, typically amateurs cheating on the internet. Maybe the makers enlisted the help of Carlsen and Leko to give their move the aura of respectability.

The Leko v Carlsen game was played 7 years ago when Carlsen was about 14 and BEFORE Houdini was written and on sale. "After 7 years, one must find an improvement"

OK so my "composition" lacks the beauty of one of SwissGambit's problems and I had probably better not take up a second career in comedy writing.

As Einstein once said, if you can't explain it clearly - you do not understand it well enough.

Ragwort was using sarcasm and irony.
I thought everyone knew this.

I took the liberty of copying this from Lars Bo Hansen's facebook page. He is a very open, sharing-oriented guy, and I am sure he won't mind, and would like the publicity!

"Learning tip: In the late 1980s and early 1990s the chess world experienced a “g2-g4 revolution” in the opening.

In a number of openings, from the Semi-Slav over the Philidor and to the English, White players pushed the g-pawn forward early on in the game, often before move 10.

I wrote about this in my book “How Chess Games are Won and Lost”. At first sight this thrust seemed to violate the classic opening principles of development, center, and king safety, but in reality the g2-g4-g5 push often had to do with the center – the Black knight on f6 is pushed away from the center.

Now a new revolution seems to be emerging – an “h2-h4 revolution”. In openings like the English (e.g. Ding Liren – Vachier Lagraeve, Biel 2013 and Wang Hao – Naiditsch, Dortmund 2013), Blumenfeld Gambit (Mamedyarov – Shoker, World Cup, 2013), and Grünfeld-Indian (e.g. Nepomniachtchi – Vachier Lagraeve, Biel 2013 and Vitiugov – Ragger, World Cup 2013).

Any time a Black g-pawn is on g6, White players seem to contemplate h2-h4-h5. This is not only to set up a possible attack on the Black king, but also indirectly influences the center.

For example, in the game Vitiugov – Ragger from the World Cup, White tested the line 1 d4 Nf6 2 c4 g6 3 Nc3 d5 4 Nf3 Bg7 5 h4!? in the Grünfeld-Indian which has gained popularity lately.

The move 8 h5!? shows how the push with the h-pawn indirectly influences the center – the knight on f6 cannot capture the annoying h-pawn because it has to keep d5 defended while 8…b4 is strongly met by 9 h6!, disorganizing Black’s pieces. So Black has to castle into an attack with a half-open h-file. 11…e6 appears to be a novelty; 11…Bb7 was played in the game Gareev – Robson from the US Championship earlier this year, but White won in convincing style.

Vitiugov too got a strong attack after the powerful exchange sacrifice 12 Rxh7! Black’s 18…Qa5? seems to be the decisive mistake; the only chance was 18…Nf7 to reinforce the king’s position.

The strong rook lift 22 Rd4! left Back with no defense.

There is one more point regarding the early push with the h-pawn, raised many years ago by my great compatriot Bent Larsen. The great Dane was famous for pushing his side pawns forward in all kinds of positions, and he once explained why he liked that strategy: if the advance of a side pawn led no-where, there would still be plenty of options left to play for a win in other parts of the board.

This was obviously important to Larsen who always wanted to play for a win; for him a draw was a half point lost. Conversely, an early advance in the center often leads to the board being cleared with little chances to continue playing for a win."

Originally posted by hedonist
I was watching a marathon on tv the other day and even the winner took over 2 hours to finish.

This just seemed wrong to me so I loaded up my car and sure enough it took me only about half an hour to travel 26 miles, and that was with stopping for a coffee.

hilarious joke

Originally posted by hedonist
I was watching a marathon on tv the other day and even the winner took over 2 hours to finish.

This just seemed wrong to me so I loaded up my car and sure enough it took me only about half an hour to travel 26 miles, and that was with stopping for a coffee.

GOLD
😀