♡ 19 ( +1 | -1 ) Well, there's no simple answer -- it's "yes" (if he makes a weaker move than a book line) or "no" if he comes up with a TN (theoretical novelty) that is better than the book line.
♡ 31 ( +1 | -1 ) And rememberThat "strong" and "weak" are relative terms. If your opponent deviates from a book line into uncharted territory, part of you will undoubtedly say "Hey, he should have played Nc4 here...now's my chance to pounce!" But you still have to come up with a way to exploit this potential weakness.
♡ 78 ( +1 | -1 ) DependsIt depends much on the player's understanding of the opening - if one side knows the main lines by heart, and notices that the other guy just stepped out of book, that knowledge will help him precious little unless he understands the reasons for the moves in the lines he's memorized. Unless the opponent's stepping out of book is a genuine novelty, then it's likely that an opponent that truly understands the opening, and isn't just playing by rote, will gain an advantage.
In practical play of course, there's psychology involved too... the knowledgeable guy/gal may just get overly confident, and overestimate the quality of his own position after the game has gone off book.... and that may lead to mistakes. Of course, if you are Kasparov, playing an amateur, you'll have a mate in 10 after the other guy steps off book. ;)
♡ 151 ( +1 | -1 ) different tactics in GK, OTB vs BlitzAlso depends on where you're playing. Players here at GK have the benefit of time to study deviations from the main lines to determine appropriate responses. Even before a deviation/novelty occurs, the player can use databases to understand better the patterns that arise as different branches occur and many stronger players can understand why certain lines may favor certain tactic and/or strategic play, why certain lines are losers, why others are drawish, etc. Thus, against stronger players that utilize time and resources available at GK, deviations might get one in trouble. Play the Grob against the 2200+ players here at GK and expect problems (LOL! Play anything against the 2200+ players and expect trouble!).
In OTB games, deviations to rarer lines that you know better than your opponent (because you've studied it and they haven't because it's rare). But certainly more general knowledge of opening theory and lines isn't going to hurt either.
In blitz games, I like to bust out the random lines and openings, especially against a player that has a strong opening knowledge but less clear play elsewhere. Get them out of that book and often the loss of tempo with a wing pawn push or flank knight move or some other odd move(s) can be recovered, often quickly. Now if I could only avoid those situations where after a random move my position deteriorates, often quickly!
♡ 45 ( +1 | -1 ) In a word, YESThat is the simple answer, but of course it is a complex question. Decrease is the key word from your question. There is a reason that book moves exist. It is because they are the best moves in the situation. That means that playing out of the book is playing lessor moves. This of course does not mean that taking the game out of the book equals a loss. It just means that the chance of a win is 'decreased'.
♡ 233 ( +1 | -1 ) coyotefan"That is the simple answer, but of course it is a complex question."
That means the correct answer must be complex, too :-)
"Decrease is the key word from your question. There is a reason that book moves exist. It is because they are the best moves in the situation. That means that playing out of the book is playing lessor moves."
You are talking about theoretical value of moves here. That is way different from practical games where finding the "refutation" is far from certain (especially at amateur level). This is especially true because IMO more and more players focus on memorizing theory moves instead of striving for better chess understanding.
There is a big difference between theory and practise. Many of the novelties Bobby Fischer used vs Boris Spassky in Reykjavik 1972 weren't better than "book moves" - in fact some of them were SLIGHTLY inferior. But he knew them better than Spassky, thereby improving his _practical_ winning chances.
And here we are talking about one of the best players of all time. If Spassky missed the best moves, you can be sure patzers like us will miss them too. How often you see an amateur player converting a small opening advantage (+/=) to a win without single inaccuracy? Almost never.
But on the other hand, very often you see self-proclaimed opening "experts" going down in flames when the opponent deviates from theory, thus preventing I-play-15-memorized-theory-moves-and-go-for-an-attack-I-found-from-page-330 plans. Getting your opponent out of book forces him to play CHESS. And more often than not folks who spend too much time for the openings aren't very good at it :-)
Also, it seems you are claiming book moves are the best moves in the situation. Not always so. Why are opening books and databases updated? Because improvements to known "book moves" are found on daily basis. It is true most of them come from GMs and IMs but it doesn't mean all the new moves found by us mortals are hopelessly bad.
"This of course does not mean that taking the game out of the book equals a loss. It just means that the chance of a win is 'decreased'."
♡ 41 ( +1 | -1 ) Well it dependsIf you are following the losing side of "book", its STILL Book ... but maybe you BETTER get out of it, and sooner the better ! :) MCO-12 was a great source of Postal Chess wins. It was particularly optimistic for the BL side of things in some lines, imo. And would declare a line "=" at the end, which would mean something like BL has 10 more moves to live :) So it was an excellent source to seek improvements against people who DID follow its Book Theory.
♡ 21 ( +1 | -1 ) to ccmcacollister,then, if I'm playing black, I should respond with the least unfavorable line (which ends at one point and i start playing chess), but, if that's impossible, leave book and play chess?
♡ 77 ( +1 | -1 ) Unsolved queryIn my humble opinion, chess, per se, is not yet solved. Therefore it is still evolving. Openings come and go, and the variations do too. But the underlying principals remain. Memorizing various lines does little to advance one's chess skills. One must be able to see and understand the principals beneath the moves. Once a person starts seeing/comprehending that, then he can start doing some serious chess and get his opponent "out of the book" rather quickly. Memorization is not a good way to play chess in my very limited experience. At least for me, I rely on studying other's games, and trying to play a few solid games at a time rather than many games. But that's only a personal preference. At least that's my opinion. I'm sure no super chess player, but do love the game!
♡ 52 ( +1 | -1 ) On the shoulders of giantsIt's been said that following a main line book opening is like riding on the shoulders of the giants! The best moves by the best players. Not all openings are subject to continuous updates some are very stable. The trick for patzers like us is to chose opening lines that are not changing frequently and suite our style of play and If you play main line openings it is much easier to find well annotated games to study and learn middle game and endgame ideas from.
♡ 51 ( +1 | -1 ) jmancusoIf the road you're on is leading to certain disaster, head for the ditch. Forget about the book, and, like you would in any other circumstance, come up with a realizable plan. Going out of book may incur some immediate disadvantage, but you will at least have a plan. Hopefully, your opponent, with neither book nor plan, will be completely lost. Guerrilla warfare 101: lead your enemy into the wilderness. With this strategy, Em. Lasker ruled chess for decades.
♡ 83 ( +1 | -1 ) If we're talking about GK gamesand my opponent deviates from whatever source I've been following and I can't find any high level games in the databases or other opening references I consult, at a minimum I ask myself, "Why not? If this is a good or at least a plausible move, why is it not showing up? Why hasn't someone tried it?" Sometimes asking that question will lead to a discovery that there's a tactical shot I can take or a stategic opportunity. Other times, it's beyond me and I can't figure out if I'm supposed to be able to obtain a significant advantage because my opponent went out of book. * In either case, it's a point I'm always waiting for in my games and I always make a note of my thoughts at that point so I can go back after the game and compare my thinking with my results - and my thinking with what Fritz or Chessmaster thought about the position at that point.