Someone please tell me how to study an opening.Do i need to remember all moves all variations or just 2-3 move?some people say you got to know the idea.Where to read the idea of an opening and what to do.How can i be sure that i know an opening?For exampple i play king's gambit.I know the moves e4 e5 f4 e:f4 accepted but when someone plays something that is not in the book how do i know how to answer his move?Help

A paste from an old forum post of mine:

1. Get firmly cemented into the mindset that the opening study is MERELY a means to get to the middle game with an equal position at the very least, no matter who your opposition is (Garry or the guy down the street) 

 Anything else that an opening (or an author) promises is fake advertising. You will not "crush" your opponents with it nor will it hide the rest of the defects in your chess against a stronger player. They will surgically dismantle you no matter how booked up you are.  

So whenever you feel you're going overboard with opening preparation,keep this in mind.

2. If you have long term goals and have a lot of time,  try learning one new move for every game you played.  That might ease the amount of information you are pumping into your brain. I've seen people claim that they can go over  4-5 opening tabiyas in 30 minutes and assimilate all the ideas, not sure how they do that or if they are rote-memorizing  ... but it is much more realistic to play the game naturally, then during the post-mortem, look up where you or your opponent deviated from the lines and "learn" the one new move that keeps you in theory. The next time you play this line, you'd be able to confidently play one more "best move" in the opening. This also allows you to "gently" adjust the thinking that picked the earlier move and nudge it towards picking the "better" move.  If you're not convinced that the book move was better, get with a stronger player and ask him.

Remember, when your opponent deviates from a theoretical line you cannot even find in book, he's either

1) Making a mistake - so in the post-mortem review where you look things up in a database/analysis software, ensure that you played the most punishing move in response. If you didn't, make sure you NOW know how to play it.

2) Playing an inaccurate move - Once again, during the review, looking at the databases should clearly indicate the best way to deal with it to get an advantage, if possible.

3) Playing a completely "do nothing" move that wastes time and gives you an advantage in terms of initiatve.

4) Playing a novelty not seen before (rare) 

Regardless, when he deviates, use your judgement (and analysis if necessary) to play your best move under the time constraints.    Don't worry if it was right or wrong....review it later with books/database software/engines or even stronger players  and *THEN* update your mental database with the right answer.

This "grow your opening tree slowly , one move per game at a time" is the best way to improve, where you KNOW you are learning the moves and not rote-memorizing them.

I recommend using software to maintain your own "repertoire/playbook" to store whatever you learn.

What to do when someone plays out of book your right thats the big difficulty.

Check the DB they may not be out of book but just playing a line you have not seen.

If that is not the case look carefully at their move see if you can detect any weaknesses. If not then develop and see what happens.

For an opening first you need a repertoire : Let me explain:- A repertoire is something like this - you play as white open with 1.e4 

your opponent's reply:-

1 e5

1 c5(sicilian)

1 e6(french)

1 c6(caro-kann)

If 1.e4 e5 then you play 2.Nf3

your opponent's reply:-

2 Nc6

2 Nf6

2 d6 etc.

If 1.e4 e5 2.Nf3 Nc6 then you play 3.Bb5 This process is like a tree and the branches continues depending on your experience, the more stronger you are the larger is the branches.

 

1. As far as memorizing the moves are concerned, you need it in a sharp openings like Sicilian najdorf or grundfeld for example. Whereas in other openings just knowing the plans and principles are enough to handle it.

2. When someone plays move not from the book it could be a novelty(in this case you are in big trouble) or he plays something rare which no one plays(if no one plays its for a reason) in this case take advantage and bring home a point. 

3. In my experience and I believe that it is the experience of others as well that knowing the main lines in an opening and some important sidelines supporting the main lines are enough for decent play.

If you understand the THEORY of your opening, you will understand how to answer the questionable move. A person that simply memorizes opening moves can easily be exploited. A lot of people can play through 15 moves at Chuck Norris speed, and then later resign because they don't know where to go from there. If you don't understand why you're making the moves, you're not learning much. As previously said, the goal of the opening is to go into the middle game with either an equal or better position. If you can do this, you played your opening just fine.

In conclusion, memorizing opening lines is generally useless, IMHO. Sure, it can give you an advantage if you're playing and your opponent plays a wrong move and you can set a trap, but if your opponent deviates from the common lines, you'll be at a loss for moves. You won't know what to do... and then you have to rely on your knowledge of opening theory, and that's what's important. Understand that, and you can respond well to any move your opponent makes.

thanks! :)

The best way to learn an opening is NOT to buy books on it or study variations to memorize them. 

Play over top master games in the openings you want to learn.  Depending on the number of games, you can filter for higher rated players or your favorite players, but play over all the search result games.   Don't spend too much time on each one, maybe 15 minutes, but go through them to the end, win, lose or draw.

In this way you will see the typical set-ups and plans and tactics for both sides, those which work AND those that fail.  You will see how the opening leads to middlegame strategies, and even the typical endings which result, and how to play them.  Understanding the ideas and the positions is far more important that memorizing lines.

Then, PLAY the openings you are researching in ALL your games - slow, turn-based, casual, blitz, rapid, all of them.  This gives you a feel for the opening as it fares "live" in action, and you can decide if it is something you like and want to play or if you need to move on to the next.

+1

Insightful and clearly stated!