Opposition - The Most Important Endgame Concept
What is meant by "Opposition" in endgame play? The answer to that question is what this article is all about.
"The Opposition", or simply Opposition, is one of, if not the most important endgame concepts to understand. It involves a process, typically in the endgame, whereby the Kings of each side maneuver against each other in order to achieve some positional and/or tactical advantage, either offensive or defensive.
The most basic, elementary scenario involving Opposition is when the minor and major pieces of both sides have been removed from play, with only King and pawn(s) remaining (i.e., a King & Pawn ending) when one or perhaps even both sides are attempting to escort a pawn to the promotion square, while the opposing King attempts to prevent it. Other, more complex scenarios involve attempts by a King to intrude or encroach into an opponent's position, while the opponent's King strives to prevent it.
Technically, the term Opposition refers to a specific geometric placement of the kings relative to each other, where the kings are said to be in a condition, or state, called Opposition. The term is also loosely used to refer to the process, procedure or technique of the kings maneuvering against each other, when they are moving into and/or out of a state of Opposition. The context of the discussion describing the situation will make it clear which of the two is intended.
Regardless of the specific scenario, in King and Pawn endings a clear understanding of the process and the technique(s) of Opposition is generally crucial for the success of either player. And without a precise understanding of the definition of Opposition one is unlikely to be able to successfully employ the technique.
The motivation for this article is that most of the internet resources on the topic that I have encountered do a poor job of defining and clarifying how to determine if Kings are in a state of Opposition. And only a fair job, at best, of explaining how it is employed in practice. Most of this article is concerned with improving upon the former shortcoming. For the latter, refer to the two sections towards the end of this article - "Practical Instruction In The Use of Opposition" and "Learning To Use Opposition - The Best Books".
In order to understand how Opposition is employed in practice, it is essential to first have a firm grasp of the definitions and criteria for a state of Opposition to exist.
Therefore, the primary purpose of this article is to define, explain what it means for two Kings to be in a state of Opposition (or not) and to describe how a player can look at a position and quickly determine whether the Kings are in Opposition.
However, I will not be explaining or describing the mechanics, i.e., the procedures of play involving Opposition in this article. For that purpose, at the end of the article I have provided recommendations for several endgame books which provide comprehensive instruction in Opposition. In addition, I have included links to several YouTube videos which illustrate the basics of the procedure for some typical scenarios. With the aid of theses resources and a little practice, I believe you should be able to learn how to use Opposition effectively and reasonably quickly.
So let's now get to the business of defining, describing exactly what Opposition means.
There are two distinct Opposition scenarios or geometries to understand. Each of these has two conditions which must be satisfied for a state of Opposition to exist. The Opposition scenarios/geometries are: 1) Opposition when both Kings are on the same rank, file or diagonal (which can be thought of, viewed, as instances of "linear" Opposition , i.e., where the kings can be connected by an imaginary straight line) and 2) Opposition where the Kings do not stand on the same rank or file, when it is referred to as "rectangular" Opposition. Note that diagonal-linear Opposition is an instance of both "linear" and "rectangular" opposition. All of this will be clarified below.
We now state the first and most general requirement (i.e., necessary condition) of Opposition, which applies to every state of Opposition:
In addition to any other condition or requirement, for Kings to be in a state of Opposition both Kings must stand on squares of the same color. As mentioned this condition is necessary but is, by itself, not sufficient. That is, additional conditions are required - one each for linear and rectangular Opposition.
Note: In the following the term 'criteria' refers to a set of conditions which, collectively, are sufficient for a state of Opposition to exist. With respect to this definition a 'condition' is necessary, but by itself not sufficient, for a state of Opposition to exist.
Criteria for linear Opposition: If the Kings stand along the same rank, file or diagonal with an odd number of squares separating them then the Kings are said to be in a state of either horizontal, vertical or diagonal Opposition respectively. Each of these states can be further categorized as being either "direct" (one square separating the Kings) or "distant" (more than one square separating) Opposition. The criteria above is sufficient for a state of linear Opposition to exist. Note also that in satisfying the criteria the Kings will stand on squares of the same color (which, as stated previously, is a necessary condition for all types of Opposition).
Direct, linear (horizontal) Opposition along 5th rank, with one (an odd number) square separating the Kings which are on squares of the same color.
Distant, linear (vertical) Opposition along b-file - three (odd no.) squares separation. Kings on squares of same color.
Direct, linear (diagonal) Opposition - one square (odd no.) separation along a diagonal. Kings on squares of same color.
The Kings are not in Opposition - due to an even number (4) of squares separating them along b-file. Note also that the Kings are not on squares of same color.
Consider now the scenario Ka8 vs Kh1. Here the Kings stand on the same color squares (white) and are separated along a diagonal. However in this scenario there is not an odd number of squares separating them along the diagonal (there are six, an even number). So, even though the Kings stand on squares of the same color they are not in a state of Opposition! Recall that Kings standing on the same color squares, while a necessary condition of Opposition, is not by itself a sufficient condition for a state of Opposition to exist.
Kings not in Opposition. Although Kings are on squares of same color, and on the same diagonal (a8-h1), they are separated by an even number (6) of squares along the diagonal, thus violating a necessary condition of linear Opposition (i.e., in linear Opposition, Kings must be separated by an odd number of squares)
However if we were to move both Kings one square each such that we now have the position Ka7 vs Kg1 (see following diagram), where the Kings are separated along a diagonal and also on squares of the same color. As a consequence there are an odd number (5) of squares separating them. So, unlike the previous case (where there was an even number of squares separating the Kings), here they are in a state of Opposition! Note that, as well as being in a state of distant, linear, diagonal Opposition, they are also said to be in “rectangular” Opposition. This is so because the Kings also stand on diagonally opposing corners of a rectangle (specifically, here, a square) formed here by straight lines drawn (along ranks and files) connecting the squares a7-a1-g1-g7, where each corner square of the rectangle is of the same color. So this is a case of linear-diagonal Opposition and also of rectangular Opposition.
Kings are in distant linear (diagonal) and rectangular Opposition. Kings are separated by odd number (5) of squares along a7-g1 diagonal. Kings stand on same color squares. Kings also stand on diagonally opposite corners of a rectangle (formed here by the squares a7-a1-g1-g7) each of which are the same color.
Criteria for rectangular Opposition: A state of rectangular Opposition is said to exist when the Kings occupy diagonally opposing corner squares of a rectangle where all four corner squares of the rectangle are of the same color. This statement constitutes a sufficient criteria for a state of rectangular Opposition to exist (note that the same color squares condition of the Kings is also satisfied). Note also, if the rectangle is a square (a specific instance of a rectangle), then the criteria for linear-diagonal Opposition (described earlier) is also satisfied.
Now consider the scenario Ke6 vs Kg2. Here the Kings do not stand along the same rank, file or diagonal, so the Kings cannot be in linear Opposition. However the Kings do stand on squares which are at diagonally opposing corners of a rectangle (the corners of which are the squares e6-e2-g2-g6) and all four of these corner squares are of the same color. So the Kings satisfy the criteria for being in a state of rectangular Opposition. Note in the earlier example with Ka8 vs Kh1, the four corner squares of the rectangle containing them were not all of the same color, so in that scenario the placement of the Kings did not satisfy the requisite criteria for being in a state of rectangular Opposition.
Kings are in rectangular Opposition. Kings stand on diagonally opposing corners of a rectangle (formed here by squares e6-e2-g2-g6), where each of the four corner squares is the same color. Note also that each of the four sides of the rectangle comprise an odd number ( here, 3 & 5) of squares - which is a necessary, but not sufficient, condition of rectangular opposition.
That's it! The definitions and associated criteria above are all you need to know to determine if two Kings are in a state of opposition. This is true irrespective of the existence of any other pieces that might also be on the board.
Summary - The Two Types of Opposition
For a state of Opposition to exist the Kings must both stand on squares of the same color. However, while this is a necessary condition, it is not a sufficient condition. The following constitute sufficient criteria for a state of Opposition to exist (all required conditions are satisfied).
Linear Opposition - If the Kings stand on the same rank, file or diagonal with an odd number of squares separating them the Kings are said to be in a state of Opposition. This is a sufficient condition for Linear Opposition. Note that when this criteria is satisfied the Kings will also stand on squares of the same color, which is a necessary but not sufficient condition for every type of Opposition.
Rectangular Opposition - If the Kings stand on diagonally opposing corners of a rectangle/square, where all four corners of the rectangle/square are of the same color, the Kings are said to be in a state of Opposition; this is a sufficient condition for rectangular opposition. When this criteria is satisfied each of the four sides of the rectangle will also have an odd number of squares, which is a necessary but not sufficient condition for Rectangular Opposition.
If a state of Opposition exists on the completion of a player's move, that player is said to "have" the Opposition. If the Kings are in a state of Opposition and one of the Kings then moves, the Kings will no longer be in a state of Opposition, and the King that had moved is said to have given up, relinquished, lost or moved out of the Opposition. If a state of Opposition exists and one of the kings moves, thus relinquishing the Opposition, then the other king (the one that did not move) is said to "have" the Opposition.
We have seen that, depending on the specific geometric placement of the Kings relative to each other one can quickly, visually, identify whether the Kings are either in, or not in, a condition or state of Opposition. One may also deduce that, depending on the specifics of the position (i.e., the placements of not only the Kings, but also any pieces and pawns that exist), and who has the move, it may be to the advantage of one of the players for a state of Opposition to exist, or to be able to take, or even to relinquish, the Opposition. Issues of advantage vis-a-vis disadvantage can only be resolved by evaluation of the specifics of the position in question. (See the sections "Practical Instruction In The Use of Opposition" and "Practicing Opposition", as well as the book recommendations, below.)
Practical Instruction In The Use of Opposition
Now that you gained a firm foundation in what it means for kings to be in Opposition (i.e., the definitions) and are able to quickly recognize when Kings are in Opposition (or not), the next step is to learn the mechanics (i.e., the process) of play involving Opposition. For that purpose I refer you to the following resources...
While the following tutorial videos are useful (in varying degrees) for gaining a sense and deeper appreciation of the mechanics of Opposition, I must make the point that any of the several endgame books I recommend further below will provide a comprehensive treatment of the mechanics (i.e., the technique) of using Opposition in a wide variety of endgame scenarios...
Chess Strategy: Opposition and Outflanking - thechesswebsite
https://www.youtube.com/watch?v=9X1Zs9HraLM&ab_channel=thechesswebsite
Pawn Promotion Using Opposition: K+P vs K Endgame...
https://www.chess.com/lessons/advanced-endgames/king-opposition
Mastering Kings and Pawns: Your Essential Guide to Endgame Success - Chess.com @fla2021 ...
https://www.chess.com/blog/fla2021/mastering-kings-and-pawns-your-essential-guide-to-endgame-success
Introduction to Opposition - Chess Antics...
https://www.youtube.com/watch?v=tECRgiGKC1o
Distant and Rectangular Opposition (Chess Opposition Part 2) - Chess Antics...
https://www.youtube.com/watch?v=wsOQBe5yBqk
What's "Opposition" in chess? And why does it matter? - Chess Vibes.....illustrates the most fundamental, basic application of Opposition. How it is employed in the most basic endgame scenario - pawn promotion in a K + P vs K endgame.....
https://www.youtube.com/watch?v=52y-iy48UoY
John Bartholomew demonstrates the most basic Opposition scenario and technique - K+P vs K endgame.....how Opposition is used to escort a passed pawn to the promotion square.....(the procedure starts at minute 4:00)...
https://www.youtube.com/watch?v=aLyRWZPXUzI
Using Opposition in a R+K vs K endgame - by John Bartholomew...
https://www.youtube.com/watch?v=Jd0meolN7w
Introduction to Opposition - by 'Hanging Pawns'...
https://www.youtube.com/watch?v=SoZPZdnYYk8
Key Squares, aka Critical Squares.....(technically the Key/Critical square concept is not essential to know, but in practice it is highly recommended and useful to understand it)...
Key Squares - Chess Antics...(only 3 parts of the video seem to be available)...
https://www.youtube.com/watch?v=hGueJO83Eww
https://www.youtube.com/watch?v=356ZghH-qv8
https://www.youtube.com/watch?v=51ZEUzwnatQ
Key Squares in King and Pawn Endgames - IM Alex Astaneh.....(2-part video)...
https://www.youtube.com/watch?v=fkFXB2V3SY8
https://www.youtube.com/watch?v=xBdlgd0utis
Learning To Use Opposition - The Best Books
The following four ENDGAME BOOKS provide extensive instruction in how Opposition is employed practice; in particular, how to use Opposition to your advantage. These books provide more comprehensive instruction than typical internet videos on the subject, and also for a greater variety of endgame scenarios...
Note: pdf copies of all of these books are available for download from Scribd.com and/or Pdfdrive.com...
https://www.chess.com/blog/RussBell/scribd-com-for-online-chess-book-reading
Essential Chess Endings Explained Move By Move Volume One Novice Thru Intermediate by Jeremy Silman. In my opinion, this book provides an excellent introduction to the topic of Opposition (see Parts 1 and 3). I highly recommend it for learning the basics of Opposition...
https://www.amazon.com/Essential-Chess-Endings-Explained-Move/dp/0875681727/ref=sr_1_1?dchild=1&keywords=isbn+number+search+0875681727&qid=1625727276&s=books&sr=1-1
a pdf downloadable copy of the book -
Silman's Complete Endgame Course by Jeremy Silman - though not quite as extensive in its coverage of Opposition as Silman's previous endgame book (above) this book nevertheless does a better than average job of explaining the fundamentals of the topic (see Parts 2, 3, 4 & 5)...
https://www.amazon.com/Silmans-Complete-Endgame-Course-Beginner/dp/1890085103/ref=sr_1_1?crid=2X3TDCSC78CJI&dchild=1&keywords=silmans+complete+endgame+course&qid=1625305535&s=books&sprefix=silman%2Cstripbooks%2C218&sr=1-1
a pdf downloadable copy of the book -
https://www.scribd.com/document/286557546/Jeremy-Silman-Silmans-Complete-Endgame-Course
Starting Out: Pawn Endgames by Glenn Flear - of the books recommended here, this provides detailed instruction in the use of Opposition for the widest variety of pawn endgame scenarios (in Chapters 1-3 & 7)...
https://www.amazon.com/Starting-Out-Endgames-Everyman-Chess/dp/1857443624/ref=sr_1_1?crid=K991LZU1RBHH&dchild=1&keywords=starting+out+pawn+endgames&qid=1628044507&sprefix=starting+out+pawn+en%2Caps%2C209&sr=8-1
a free pdf downloadable copy of the book -
https://www.pdfdrive.com/starting-out-pawn-endgames-e175995247.html
Pandolfini's Endgame Course by Bruce Pandolfini - Similar to Silman's Complete Endgame Course (above), this is a complete endgame course covering all of the important, fundamental endgame concepts and techniques appropriate for all amateur players, Beginner through Expert level (2000 Elo). The book contains many lessons on Opposition (roughly 37 on the topic, by my count). I particularly appreciate the succinct, one-lesson-per-page format (239 total lessons), making each lesson a relatively quick study.
A minor (to me) annoyance is that the book contains 37 typographical errors relating to moves. Despite the typos, the book is well written and very instructive. Happily, all of the typos have been identified, collected and corrected in the following errata...
http://www.glennwilson.com/chess/books/pec_errata.html
a free pdf downloadable copy of the book -
https://www.pdfdrive.com/pandolfinis-endgame-course-d116188171.html
Endgame Workshop by Bruce Pandolfini - Objectively, in terms of content and instructional value this is an outstanding introductory endgame book with detailed explanations of concepts and techniques. In particular, for our purposes, it contains extensive treatment of Opposition with many examples in a variety of scenarios (see Chapters 1, 13-16). However, relating specifically to his writing style I found Pandolfini's explanations to be often excessively wordy, confusing and a chore to read (your experience may differ). For this reason alone, in terms of learning the Opposition I tend to prefer the previously cited endgame books...
https://www.amazon.com/Endgame-Workshop-Principles-Practical-Pandolfini-ebook/dp/B0033AGA6C/ref=sr_1_1?crid=UVN7KHWBLG8O&dchild=1&keywords=endgame+workshop&qid=1620792833&s=books&sprefix=endgame+workshop%2Caps%2C208&sr=1-1
a pdf downloadable copy of the book -
Practicing Opposition
Once you've gained exposure to the basic procedures and techniques of play involving Opposition provided by the videos and books cited above, I strongly recommend to check out the following instructional studies/puzzles for the purpose of gauging your understanding and skill at using Opposition. These videos are essentially interactive puzzles intended to clarify several basic Opposition scenarios and their associated techniques which are useful in K+P endgames. If you cannot follow or solve the procedures, it is time to review the instructional resources - videos and books - cited above until you can.
https://lichess.org/practice/pawn-endgames/key-squares/xebrDvFe/o3Hq4RZ0
https://lichess.org/practice/pawn-endgames/opposition/A4ujYOer/QP6WT68l
With study and practice Opposition will become easy. You can do it!
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For more articles on other chess topics, including helpful chess resources and book recommendations, be sure to check out my Chess.com blog.
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