A working glossary for the whole course, in plain language and in the course's own words rather than the book's. It starts from the "Key Terms and Concepts" list at the back of How to Win at Chess and adds a small number of terms (marked added) that the chapters lean on heavily but the book's own list leaves out. Every term that is actually taught somewhere in the chapters carries a "See" link to the section that teaches it.
A
Attack
A piece is attacking an enemy piece when it could capture it on the next move and actually come out ahead by doing so. Simply being able to reach a square isn't enough — if capturing there would just hand back the piece for nothing, it isn't a real attack. See Ch. 07 §1 →
Attraction
A tactic where you give up material to force (or tempt) an enemy piece onto a specific square, so that once it lands there it becomes vulnerable to a follow-up attack, often as part of a mating net. See Ch. 14 §8 →
B
Back-Rank Mate added
A checkmate delivered by a rook or queen sliding all the way down to an enemy's home rank, when that king is boxed in by its own pawns and has no escape square. Leaving a castled king a luft is the standard way to prevent it.
A pawn that still has friendly pawns on the neighboring files (so it isn't isolated) but can't safely advance because the square ahead of it is controlled by the enemy, and no other pawn is in position to support that advance. It tends to need constant piece protection. See Ch. 15 §1 →
Battery
Two or more of your own pieces lined up together on the same rank, file, or diagonal, so the piece in front can attack while the piece behind backs it up — a queen with a bishop or rook behind it is the classic pairing. See Ch. 05 §3 →
Bishop Pair added
Owning both of your bishops while the opponent has traded one of theirs away. Because each bishop only ever travels on one color, having both means covering every square on the board, which is a real long-term asset once the position opens up.
Parking a piece directly in front of an enemy pawn so it physically cannot advance. It's an especially effective way to neutralize a pawn that has no support to push it forward or trade it off. See Ch. 15 §1 →
C
Capture
Moving one of your pieces onto a square held by an enemy piece, which takes that piece off the board for the rest of the game. See Ch. 00 §3 →
Castling
A one-time special move where the king hops two squares toward a rook and that rook jumps to the square the king passed over, tucking the king away safely and bringing the rook into play at the same time. It's only legal if neither piece has moved yet, nothing stands between them, the king isn't currently in check, and the king doesn't pass through or land on an attacked square.
A direct threat to capture the king on the next move. A player in check must immediately get out of it — by moving the king, blocking the attack, or capturing the attacking piece — since any move that leaves the king in check is illegal. See Ch. 00 §4 →
Checkmate
A check that can't be escaped by any of the three usual options — moving the king, blocking, or capturing the attacker. Checkmate ends the game immediately in a win for the attacking side. See Ch. 00 §4 →
Closed Position
A position where most of the pawns are still on the board, locked against each other, so files and diagonals stay clogged and pieces struggle to cross the center. Progress usually comes from slow maneuvering and pawn breaks rather than direct confrontation. See Ch. 08 §4 →
Counterplay
Active chances a player under pressure generates for themselves — a threat or plan of their own that forces the attacker to worry about defense too, instead of just piling on unopposed. See Ch. 15 §1 →
D
Danger Levels
A reminder to weigh threats against each other before reacting: if one of your pieces is attacked but you have a bigger threat of your own (say, a check or an attack on something more valuable), it's often correct to ignore the smaller threat and press your own idea instead. See Ch. 14 §2 →
Defend
A piece defends another when it's placed so that, if the enemy captures the defended piece, the defender can recapture on that same square. See Ch. 07 §2 →
Deflection
A tactic that forces a defending piece to abandon the square or piece it was guarding, usually by hitting it with a bigger threat it can't afford to ignore, so that the thing it was protecting is now left exposed. See Ch. 14 §8 →
Development
Bringing your knights, bishops, rooks, and queen off their starting squares and onto more active ones early in the game, so your pieces are ready to fight for the center instead of sitting idle. See Ch. 02 §2 →
Discovered Attack
Moving one of your pieces out of the way so that a different piece behind it suddenly attacks something — often the moving piece creates a second threat of its own at the same time, which is what makes the tactic so strong. See Ch. 07 §6 →
Discovered Check
A discovered attack where the piece being uncovered is now checking the enemy king. It's especially dangerous because the piece that actually moved is completely free to do anything useful, since the opponent has to deal with the check first no matter what. See Ch. 07 §6 →
E
Elo
The numeric rating system used to estimate a player's strength relative to everyone else, named after its creator Arpad Elo. Winning gains you rating points, losing costs you some, and the size of the swing depends on how big a gap there was between the two players' ratings. See Ch. 00 §6 →
En Passant
A special pawn capture allowed only in one specific situation: if an enemy pawn uses its two-square first move to land right beside one of your pawns, you may immediately capture it as if it had moved only one square. The option disappears forever if you don't use it on the very next move.
The final stage of the game, once a large share of each side's pieces and pawns has already been traded off the board. Technique matters enormously here — reaching a winning material edge is wasted if you don't know how to actually convert it. See Ch. 04 §1 →
Exchange Up/Down
Describes an unequal trade of a rook for a minor piece (a knight or bishop). The side that ends up with the rook is "up the exchange," and the side left with the minor piece is "down the exchange," even though giving up the exchange can sometimes be worth it for activity or attack. See Ch. 15 §4 →
F
Fianchetto
Developing a bishop onto the long diagonal one square in from the corner, by first pushing the neighboring knight-pawn out of the way (g3/Bg2 or b3/Bb2 for White; g6/Bg7 or b6/Bb7 for Black). See Ch. 03 §3 →
File
One of the eight vertical columns of the board, lettered a through h from White's left to right. See Ch. 00 §1 →
Forced Checkmate
A sequence of moves, usually checks or threats the opponent can't ignore, that leads to checkmate no matter how the defender responds along the way. See Ch. 05 §4 →
Fork
A single move that attacks two or more enemy pieces at once, so the opponent can only save one of them. Knights are especially dangerous forkers, since a piece they attack usually can't attack them back.
An opening in which a player deliberately hands over some material, usually a pawn, in exchange for a faster lead in development, extra central control, or some other lasting positional edge. See Ch. 12 §1 →
Golden Moves
A model of what the first ten moves would look like if you got to develop completely uninterrupted: claim the center, bring both knights and bishops out to active squares, and castle. Real opponents always interfere, so treat it as a target to aim toward rather than a literal plan. See Ch. 02 §3 →
I
Insufficient Checkmating Material
A situation where neither side has enough material left to construct a checkmate against the other, no matter how the remaining moves are played — for instance, a lone king and knight against a bare king. The game is scored as an immediate draw rather than played out. See Ch. 06 §6 →
Isolated Pawn
A pawn with no friendly pawn on either neighboring file, meaning no other pawn will ever be able to defend it. It isn't automatically bad — one backed up by active pieces can be useful — but it's a long-term target if it isn't. See Ch. 15 §1 →
K
Keeping the Tension
Choosing not to make a capture even though the position allows it, because trading right away would help the opponent more than it helps you. Both sides simply develop around the standoff until one side is forced to resolve it, or finds a moment where resolving it favors them. See Ch. 15 §5 →
King Opposition
A face-off in king-and-pawn endgames where the two kings stand directly across from each other with exactly one empty square between them. Whichever side is forced to break that face-off first usually has to give ground, which is why fighting for the opposition is a core endgame skill. See Ch. 13 §2 →
Knight Opposition
A technique for mating with a lone queen (or rook) against a bare king without ever giving a check too early: you place your queen on a square that would give check if it moved like a knight, which boxes the enemy king in from a safe distance while you shrink its space. See Ch. 04 §3 →
L
Luft
A little breathing room for a castled king, usually made by pushing one of the pawns shielding it forward one square, so the king has an escape square and can't be trapped on the back rank. See Ch. 05 §2 →
M
Middlegame
The phase of the game between the opening and the endgame, once each side's pieces are developed and the position has moved past known opening theory into fresh territory. See Ch. 13 §1 →
O
Opening
The first phase of the game, where both sides fight for the center, bring their pieces out, and get their king castled to safety. Because so much has already been analyzed, it usually pays to borrow known, tested opening moves rather than improvise. See Ch. 02 §1 →
Open Position
The opposite of a closed position: many pawns have already been traded off, so files and diagonals stand open and pieces can see and strike clear across the board. See Ch. 08 §4 →
Outpost added
A square, usually deep in enemy territory, that no enemy pawn can ever attack and that isn't worth the opponent's while to challenge with a piece. Knights especially love sitting on one, since a friendly pawn defending the outpost doesn't get in the knight's own way the way it would block a bishop.
A pawn with no enemy pawn left on its own file or either neighboring file to block or capture it on its way forward, meaning nothing but pieces can stop it from eventually promoting. See Ch. 13 §2 →
Pawn Break added
A pawn push aimed at forcing open a file or diagonal, or clearing a square for a piece, by provoking a trade that reshapes the pawn structure in your favor. It's the standard tool for cracking open a closed position rather than trying to force pieces through a wall of pawns.
A diagonal row of same-colored pawns where each one (except the pawn at the very base) is protected by the pawn standing behind it. See Ch. 15 §1 →
Pawn Structure
The overall arrangement of both sides' pawns in a given position. Since pawns move the least and shape what every other piece can do, recognizing a familiar structure often reveals the right plan before you've calculated a single line. See Ch. 15 §1 →
Perpetual Check
An unbroken string of checks that a losing side can sometimes deliver forever, forcing a draw by repetition regardless of how far behind on material they are. See Ch. 06 §3 →
Philidor Position added
A key drawing setup in rook-and-pawn endings: the defending rook sits on the rank directly in front of the enemy pawn, keeping the attacking king from crossing it, and drops back to check from behind the moment the pawn advances onto that rank.
A pin where moving the pinned piece is completely illegal, because the king itself is standing directly behind it on the same line. See Ch. 07 §4 →
Pin (Relative)
A pin where the pinned piece is legally allowed to move, but doing so would expose a more valuable piece behind it to capture — so moving it is legal but costly. See Ch. 07 §4 →
Promotion
The rule that a pawn reaching the far end of the board must immediately turn into a knight, bishop, rook, or (almost always) a queen — there's no limit to how many pieces can be promoted this way in a single game. See Ch. 00 §3 →
R
Rank
One of the eight horizontal rows of the board, numbered 1 through 8 from White's side to Black's. See Ch. 00 §1 →
Removing the Defender
A tactic that attacks or captures whatever piece is guarding a mating square or another valuable piece, clearing the way for the idea that guard was preventing. See Ch. 14 §5 →
Resignation
Giving up the game voluntarily, before checkmate actually occurs, once a player recognizes the position is hopeless — a serious material deficit or an unavoidable mate a few moves off are typical reasons. See Ch. 01 §3 →
Rook Lift
A plan to bring a rook forward off the back rank and then swing it sideways into the attack, reaching squares or files it couldn't get to along its own rank. See Ch. 15 §4 →
S
Sacrifice
Deliberately giving up material — more than you immediately get back — in exchange for an attack, faster development, or a calculated win later on. It should be a calculated investment, not a hopeful gamble. See Ch. 14 §8 →
Skewer
A pin in reverse: you attack a valuable piece first, and when it's forced to move out of the way, you capture whatever less valuable piece was standing behind it.
A checkmate delivered by a knight in its distinctive L-shaped pattern, possible only because the enemy king has been completely walled in by its own pieces with no escape square left.
The number of squares your pieces control in the opponent's half of the board. A big space advantage cramps the enemy's pieces while giving your own room to maneuver, though it isn't permanent — it shifts as pieces get traded and squares change hands. See Ch. 08 §3 →
Stalemate
A position where the player to move isn't in check but has no legal move available at all. Rather than a loss, this ends the game as a draw. See Ch. 00 §4 →
Strategy
Longer-term planning based on reading who stands better in a quiet position and why, then steadily working toward an advantage over many moves, rather than cashing in something immediate the way a tactic does. See Ch. 08 §1 →
T
Tactics
Short, forcing sequences of moves that win material or force checkmate right away, as opposed to the slower, longer-term planning of strategy. See Ch. 08 §1 →
Tempo
A move that gains time by forcing the opponent into a purely defensive reply, so you effectively get to make an extra useful move while they're busy responding to your threat. See Ch. 10 §3 →
Trade
An exchange where one piece captures an enemy piece and the opponent recaptures with a different piece, usually of similar value. A trade reshapes the whole position — not just the material count — so it's worth judging by more than points alone. See Ch. 15 §5 →
V
Variation
A named branch of moves that splits off from a shared opening once one side deviates from another well-known line. See Ch. 02 §4 →
W
Weakness
A piece, pawn, or square that isn't adequately defended and can actually be reached and exploited — a weakness only counts if there's a real way to attack it, not just in theory. See Ch. 08 §2 →
Z
Zugzwang
A situation where a player would be perfectly fine if they could just pass, but since they must move, every legal option available to them makes their position worse. See Ch. 13 §5 →
Zwischenzug
An "in-between move": instead of playing the expected, obvious response, you first insert a strongly forcing move (usually a check or a big threat) that the opponent must answer, and only then follow up with the original idea. See Ch. 14 §6 →