Learning a chess opening can be a daunting prospect. Openings often seem complicated, and there’s a huge body of “opening theory” available for study. So much information can make it difficult to know where to begin.

This guide will describe how to effectively learn a chess opening without drowning in excess information or spending lots of time poring over obscure opening variations. Following the guide's steps and recommendations will enable you to study chess highly efficiently, ensuring that you're making good use of your study time.

Step 1: Locate an Opening That Looks Interesting to You

In order to really enjoy the process of learning an opening, you should choose an opening that you think is interesting or fun to play. A useful resource for locating reputable openings is the website chessgames.com, which offers lots of grandmaster-level games for users to peruse. If you see an opening there that you like, you can rest assured that it’s favored by the best players in the world.

Here are a few suggestions to aid you as you choose an opening to learn:

Consider the sorts of chess games you enjoy most. Do you like crazy, tactical, highly aggressive games? Look for openings that involve lots of attacking. Do you prefer quieter, more positional games with an emphasis on maneuvering? Pay close attention to openings that seem to build up slowly
Don't spend time trying to analyze the openings you're looking at or attempting to absorb every nuance. That can come later once you've found an opening you know you want to learn. For now, just click through the first few moves of openings and see if anything sticks out as something you'd like to play

Step 2: Read About the Basic Ideas of the Opening and Examine a Few Example Games

After choosing your opening, you’ll want to understand some of the basic ideas involved in playing it. Here are some useful research tips:

chessgames.com is helpful for this task; search for the opening you’ve chosen to learn and you'll see a listing of complete games in which it was played. Click through a few of them, but don’t feel compelled to see the whole game; you mostly want to look out for what positions generally arise after the first 10-15 moves

Try searching the name of your opening online; sites like Wikipedia often have entries that detail the basic concepts of the opening. If you find that clicking through games doesn’t help you understand the opening, it’s worth seeking out these prose explanations
Focus on core concepts and goals of the opening, not on every variation or nuance. You'll learn those specifics naturally as you study your opening; it's not a very good use of time to absorb technical details before you have a good understanding of the fundamentals of your opening

Step 3: Memorize the First 8-10 Moves of the "Main Line"

Main line refers to the most commonly played variation of an opening. The main line contains the moves you’ll be most likely to see.

A great website to help you is 365chess.com; it allows you to examine an opening and displays the most popular move in each position. The first eight to ten moves for both sides is more than enough to get started with an opening—don’t drown in memorization or theory!

Step 4: When Something New Happens That You Don’t Recognize, Look Up the Correct Response

Each time something new arises in your opening that you haven’t seen before, be sure that after the game, you go look up what happened by using a chess engine or an openings database. These should be your goals:

Find out what the best response is to the position you encountered. 365chess.com is very useful for determining the most popular response to an unfamiliar position

Avoid memorization. Just learn the next one or two moves and apply them next time you encounter the position

As you repeat this step over and over, you’ll continue to learn more and more about your opening without ever spending lots of time memorizing lines and theory you’ll never see; this way, you only look up situations you’ve actually encountered.

Step 5: Use an Analysis Engine to Polish Your Opening

There are many powerful computer programs called "analysis engines" that can help you examine your chess games so you can understand where you're going wrong and how you can improve. Once you've become more advanced with your opening, this is the most time-efficient way to locate the subtle mistakes you might be making.

If you find yourself getting outplayed in the opening and you're not quite sure what you're doing wrong, it's helpful to step through your game move-by-move with an analysis engine; you can read its suggestions and examine them more closely so that you have an idea of what to play for next time. Here are a few tips regarding analysis engines:

Stockfish is an excellent free analysis engine; if you're not sure which engine to try, Stockfish is a good choice. There's even a Mac OSX/iOS app for Stockfish
Analysis engines use a point-based system to evaluate who has an advantage in a given position--be sure to read the documentation for the engine you're using to find out the meanings of the points it assigns
If you see the point evaluation drastically favor your opponent after any single move when you were previously even, that means you're missing winning tactics. If the points slowly shift in your opponent's favor, you're probably getting outplayed positionally. If you notice either of those trends in your own games, you'll know what area to focus on