Pawn Structures 101 - Part I

by Dr. Jason Morris

Introduction

I want to share with you all some tips that boosted my rating from USCF1800 to 2000. First, let me ask you about your chess games:

• Do you get bad positions from the opening? (I did!)
• Do you have trouble finding a plan in the middlegame? (Yep!)
• Does it seem that your pieces don't work together as well as your opponent's? (This drove me crazy!)
• Do you lose many of your endgames? (Very frustrating!)

Like I did, it could be that you are having trouble with your pawn play. By studying some basic pawn theory, I extracted much more value from my opening study. What to do in the middlegames became more clear in terms of which pawns to push and which to leave alone, and I became more vigilant about how my pawn moves affected possible endgames. I continue to refine and polish this aspect of my game. You can too!

Let's dive in!

A pawn structure, or just "structure", is the arrangement of pawns in a given position. There are many great books written about this topic, as well as many good articles. I will give some references at the end of this article. One of the best that I found was "Pawn Structure Chess" by GM Andy Soltis. IMHO the newest edition is not as good as the original; many of the examples have typos. If you can get past the atrocious terminology, "Pawn Power in Chess" by Hans Kmoch is a classic. I believe there is a jargon-free translation somewhere.

In this article, we will start by talking about pawn structures as they result from the opening. In fact, what I am going to advocate here is that you approach the study of any opening from the point of view of its pawn structure first. Once you have mastered all the basic themes and ideas of the structure, you will be able to understand and appreciate the opening's different variations.

Moving Pawns is a Trade-Off
The late great Bobby Fischer noted that you "have to give some squares to get some squares."

• When you move pawns, more squares in your territory will be left unprotected. 
• The squares that you "get" should be worth more than the ones you "give" potentially to your opponent. 
• Your pieces should be positioned to defend the squares not covered by your pawns. 
• Each opening can be categorized by the squares that it forsakes versus the ones it tries to acquire.
• The relative value of any given piece is largely a function of how it coordinates with the given pawn structure. This is particularly true of bishops and knights.

If you learn these trade-offs for squares and how they affect the quality of your pieces, your playing strength will greatly improve -- guaranteed!

Don't Memorize Openings
I learned (the hard way!) that memorizing opening variations without first understanding an opening's pawn structure is a complete waste of time. When studying a new opening, the first thing I look at is the resulting pawn structure. This will tell you where the best squares for each piece should be. The opening structure forms a skeleton or framework for the middlegame. By understanding what features and actions a given structure provides, we can understand how to play the resulting middlegames (from both sides!). In fact, different openings can result in the same pawn structure. Masters use knowledge of pawn structures to determine what the best plans are for any given position.

Move Order Matters
The term transposition is used to describe the situation where one structure changes into another, particularly in the opening. Let's see how this works in the diagram below.

This position started from a French Defense (1. e4 e6), but after the moves 2. d4 c5 3. Nf3 cxd4 4. Nxd4 a6, we have a Kan Variation of the Sicilian Defense. Had white opted for 3. d5, the structure would have been more favorable to white, so the order of the pawn moves matters. If black really wanted to play the Kan, he should use the order 1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 a6, which avoids losing space in the center to white's d5 thrust.


Don't Fight the Structure
One of the most important lessons that I learned when I was USCF 1800 or so was not to fight the structure. By this I mean don't play pawn moves that are not strategically in accord with the structure. Doing so is a sure way to come to grief against a stronger player who will seize immediately on your errors. Unlike inferior piece moves which are often recoverable, bad pawn moves are irrevocable. Once made, they can permanently damage your game, often irreparably. Therefore, you should make only the minimum number of pawn moves to achieve your opening objectives of control of an equal portion of the center and to complete your piece development -- nothing more.

Opening Types vs. Pawn Structures

Chess openings fall into one of three main categories according to pawn structure:

• Open games
• Semi-open games
• Closed games

In open game pawn structures, the four center squares (e4, d4, e5, d5) have a high probability of being completely cleared of pawns. This results in many open diagonals and files. Open games are characterized by the pawn structures that arise after 1. e4 e5, or more commonly "double king pawn" openings. These games tend to be very fast paced and tactical because pieces can come into contact with each other very quickly. Kings especially can fall under quick attack along open lines (diagonals, ranks, and files).

In closed game pawn structures, there is at least one pair of pawns facing each other in the center, usually but not always pawns at d4 and d5. Hence, games that begin 1. d4 d5 usually lead to closed positions where the center is blocked with pawns and there are few if any completely open files and diagonals. These games tend to be much slower paced, with more maneuvering.

Semi-open games result from asymmetrical replies to 1.e4, where the distribution of central pawns and half-open files becomes unbalanced. Examples of such openings are the ever popular Sicilian Defense (1. e4 c5), the Caro-Kan (1. e4 c6), and the Center Counter (Scandinavian) Defense (1 e4 d5). Such openings can result in opposite-side castling and pawn storms.
 

Pawn Structure Terminology

Here are some basic concepts about pawn structures. Mastering these will help you (a) evaluate positions to know who stands better and (b) to help you analyze and understand all chess openings.

Backward Pawn (weakness) A pawn that cannot be protected by any other pawns. In Diagram 1, the pawn on d6 is a backward pawn since it cannot be protected by any other black pawns. It is especially vulnerable to attack along the half-open d-file by white's rooks and queen. Despite the weakness of d6, black is not without recourse here. For example, he has the moves b7-b5 to attack c4 and the moves g7-g6, f7-f5 to attack e4 and build a pawn center. Also, if black can maneuver a knight to d4, it will mask the d6 weakness.  In general, avoid creating backward pawns in your position.   Attack backward pawns in your opponent's position.	Diagram 1. The classic backward d-pawn from the Sicilian Defense.
Isolated Pawn (weakness) A pawn that has no pawns on either side. In Diagram 2, white's d-pawn is isolated. This type of pawn needs constant protection. Whether or not this position is good or bad for white depends on whether or not the d-pawn can advance to d5 at some point. Also, the protected e5 square can be used as an outpost for white's pieces - usually a knight. Avoid creating isolated pawns in your position.   Attack isolated pawns in your opponent's position.	Diagram 2. An isolated queen pawn (isolani) position.
Doubled Pawn (weakness) Two pawns on the same file. In Diagram 3, white has traded his white squared bishop for a knight on c6. Black followed the general principle of capturing towards the center with pawns, but this creates two weaknesses: the isolated a-pawn and the doubled c-pawns. Despite being so close, doubled pawns cannot protect each other.  In Diagram 3, white would like to play 1. dxe5 dxe5 because then black's two c-pawns would be isolated as well as doubled, making them easier to attack. Recapturing on c6 with the d-pawn is black's preferred option in master play, but this too has pitfalls. See Diagram 8a. Avoid getting doubled pawns if you can.  If you cannot, then try to get some compensation for them (e.g. the pair of bishops, an open file, etc.)	Diagram 3. Doubled pawns from the RuyLopez - Exchange Variation.
Hole (weakness) A square that cannot be protected by pawns. In Diagram 4. black has captured a white knight at f3. White had to recapture with his g-pawn so that he did not lose his d-pawn. The result is that white has a serious hole on the f4 square. This is a perfect place for a black knight, from where it can attack e2, d3, g2, and h3 near white's king. Note that though white's f-pawns are doubled and his h-pawn is isolated, he often has the bishop pair and the half-open g-file for counterplay. Avoid making holes in your pawn structure.   Try to move your pieces into the holes in your opponent's pawn structure.	Diagram 4. White has multiple pawn weaknesses.
Levers (strategic move) Pawns that can move to attack stationary pawns on adjacent files. In Diagram 5, arising from the King's Indian Defense, white's important lever is the move c4-c5 attacking d6. Black's lever is f7-f5 attacking e4. Note that the d6 pawn and the e4 pawn cannot avoid the lever actions because they are blocked by the d5 and e5 pawns, respectively. Use lever moves to open lines and to disrupt your opponent's pawn structure, particularly around his king.  Attack pawn chains at their base and head with lever moves.	Diagram 5. Levers in the KID.
Pawn Chain (strategic element) A diagonal line of pawns that mutually protect each other. In Diagram 6, the white pawns from b2 to e5 form a self-protecting chain. Play on the side of the board in which your pawn chain "points" (i.e., where you have more space).	Diagram 6. The classic French Defense pawn chain.
Base (strategic element) The first pawn in a pawn chain. Head (strategic element) The last pawn in a pawn chain. In Diagram 7, the pawn at e5 is the head of white's chain.  In Diagram 7, the pawn at b2 is the base of white's chain. This position arises from the French Defense. White has built a pawn chain driving into black's kingside. Black's counterplay depends on his levers c7-c5 and sometimes f7-f6. Black would like to play 1. .. cxd4 2. cxd4 and create a backward pawn on d4. Then he could attack it with a knight on c6 or a queen on b6. Use levers to attack the base and head of pawn chains. Be careful about creating holes when attacking head pawns.	Diagram 7. Action against pawn chains.
Passed Pawn (strategic advantage) A pawn that cannot be stopped by enemy pawns. Pawn structures should always be evaluated as to their potential to produce passed pawns. Diagram 8a comes from the Exchange Ruy Lopez. If play continues 1. .. exd4 2. Qxd4 Qxd4 3. Nxd4, then white's majority on the kingside will produce a passed pawn where as black's cannot due to the doubled c-pawn. This gives white a long-term strategic advantage. This advantage is counter-balanced in practice by black having the bishop pair. In Diagram 8b, both white and black have passed pawns. Evaluate the position and give the result.	Diagram 8a. Pawn majorities. Diagram 8b. White to play. What is the result?
Hanging Pawns (strategic element) Connected pawns unopposed on adjacent open files. Can be used for attack and to control central space. Can (potentially) create a passed pawn. Can come under attack along half-open files. Lose strength when one pawn must move forward.	Diagram 8. Hanging pawns.

Summary 

Chess openings should be studied from the point of view of the resulting pawn structure. If you understand the resulting structure in terms of its strengths and weaknesses, then you will understand how to play the resulting position, both as white and as black. The pawn structure dictates where the most effective squares are for your pieces and your opponents'.

• Holes in your opponents pawn structure should be exploited by posting a piece on that square. The best piece to post is often a knight. 
• Backward pawns on open files should be attacked by doubling and even tripling major pieces (rooks and queens) against them. 
• Make pawn exchanges that isolate, double, or otherwise expose your opponents pawns to attack. 
• Make piece exchanges that create pawn weaknesses in your opponent's camp. 
• Whenever you make pawn moves, ask yourself "How does this impact my endgame? What squares am I getting and what squares am I weakening?" 
• When you make pawn moves (particularly near your king), always consider how you will cover the resulting weakness(es) and anticipate how your opponent will respond. (e.g., what lines and diagonals am I opening? Am I creating invasion points for my opponent's pieces or targets for my opponent's pawn advances?)

Of course, there is much more to say about this topic :-) We'll save that for later articles. All comments and feedback welcome!

References

https://en.wikipedia.org/wiki/Pawn_structure
http://www.chess-game-strategies.com/pawn-structure.html
https://www.chess.com/article/view/how-to-ruin-your-pawn-structure
https://www.chess.com/blog/whiskeytown/pawn-power-in-chess-by-hans-kmoch 
https://www.chess.com/video/player/pawn-structure-101-every-opening-explained