1.1 Fork: One piece attacks two or more enemy pieces simultaneously.
1.2 Pin: A piece is unable to move because doing so would expose a more valuable piece (or the King) behind it (only bishops/rooks/queens can do this)
1.3 Skewer: A piece attacks a valuable enemy piece, forcing it to move and exposing a less valuable piece behind it; pin has more valuable piece behind less valuable one; skewer is the reverse; only bishops/rooks/queens can do this
1.4 Discovered Attack: Moving a piece to unblock a line of attack for a friendly piece standing behind it. Also includes Discovered Check and Double Check.
1.5 Hanging Pieces: Leaving a piece unprotected and exposed to capture.
2. Breaking defences
2.1 Overloading: Targeting a defensive piece that is trying to protect too many squares or pieces at once.
2.2 Undermining: Capturing or driving away a defending piece to leave an enemy target vulnerable (also called "Removing the Defender").
2.3 Deflection: Forcing a key defender to move away from its job
2.4 Decoy: Forcing a piece to a bad or “poison square”
2.5 Pawn break through: Breaking through a pawn shield to attack the king.
3. Combos
3.1 Sacrifice: Deliberately giving up material to gain a tactical or positional advantage (e.g., to clear a square or open a line); Includes Queen Sacrifice, Exchange Sacrifice, and Clearance Sacrifice
3.2 Intermezzo: Playing a surprising "in-between" move that creates a new threat before responding to the opponent's previous move.
3.3 X-Ray attack: Attacking through a piece to pressure or target what lies behind it; only bishops/rooks/queens can do this
3.4 Battery: Lining up two pieces in a row (bishop, rook, or queen) to form an attack across a line or diagonal
4. Rare but powerful
4.1 Piece trap: Forcing a piece into inescapable capture
4.2 Interference: Placing a piece to block an enemy line of defense or communication
4.3 Windmill: A repeated series of discovered checks that lets you capture material between checks; only bishops/rooks/queens can do this
4.4 Desperado: Using a piece that will be lost to try to capture the best opponent piece along the way
5. Endgame wins
5.1 Simplification: when winning, trade pieces with opponent to avoid complicated games that could lead to mistakes
5.2 Zugzwang: (move compulsion) – Any move worsens your position because you are forced to move
5.3 Smothered Mate: Checkmate delivered when the king is trapped by its own pieces, usually via a knight.
5.4 Underpromotion: Promoting a pawn to a piece other than a queen for tactical reasons
6. Endgame draws
6.1 Forced stalemate: Deliberately engineering a position with no legal moves but not in check.
6.2 Perpetual check: Checking repeatedly so the opponent cannot escape, forcing a draw.
6.3 Fortress: create a protected wall so opponent can’t penetrate without a sacrifice
B. Positional Assets
1. Pawn structure
1.1 Passed pawn: Pawn that has no opposing pawns on its own file or the files next to it that can stop it from promoting - i.e. once it starts moving forward, only non pieces can stop it from getting promoted; They are strong (especially in end games) because they threaten promotion, forcing the opponent to react
1.2 Supported passed pawn: Passed pawn with another piece there ready to protect it (tip - push the supporter first, then advance the passed pawn when the defense is fixed)
1.3 Outside passed pawn: Passed pawn far from the main action, used to distract the opponent king
1.4 Protected passed pawn: Passed pawn defended by another pawn
1.5 Pawn majority: Can create a passed pawn.
1.6 Connected pawns: Advance and defend each other.
2. Material Assets
2.1 Active Piece: Piece that is well placed, mobile, and influencing important squares or targets, often creating threats or restricting the opponent; Examples - outpost Knight, Bishop on a long, open diagonal, Rook on an open file, Queen safely centralized and creating threats, King in end-game centralized and creating threats
2.2 Passive Piece: Piece that is stuck behind pieces or defending pieces
2.3 Passive Square: Square where a piece is placed without influence, meaning it doesn’t control important squares, attack, or defend anything, making the piece essentially inactive;
2.4 Good bishop: Bishop whose own pawns do not block it and that operates on squares the opponent cannot easily control or challenge; Good bishops have pawns mostly on opposite color, open diagonals it can use freely, opponent targets on its color, and mobility
2.5 Bishop pair: Having both of your bishops when your opponent does not; They are strongest in open and semi-open positions because they work well together to create pressure from afar; In endgames, they can also dominate a pair of knights; they tend to be worse than Knights when you are in Closed Positions with Locked Pawn Chains or when the opponent has strong outposts for knights
2.6 Piece Coordination: When your pieces work together toward the same goal, supporting each other so that their combined effect is stronger than any piece alone (ex. Batteries, Outposts, King supporting a passed pawn in the endgame)
2.7 Blockade: Piece(s) block the advancement of pawns to get promoted or King Blockade, which blocks the King from moving to key squares or supporting pawns
3. Space
3.1 Space advantage: You control more territory on the board, giving your pieces more room to move while restricting your opponent’s; Examples of how to get it - advance pawns that control important squares (ex. center control), restrict opponent piece movement (not just attacking them); It helps because it makes it easier for you to create attacks and harder for opponent to defend them
3.2 Outposts: Strong square (usually in the opponent's territory) where a piece can sit safely because it cannot be chased away by opponent pawns (typically a knight protected by pawn)
3.3 Strong square: Square where a piece can sit safely and effectively, controlling important territory (ex. Rank 4th, 5th, or 6th; outpost setup) because the opponent cannot easily challenge it with pawns vs weak square that cannot be defended or controlled by a pawn
3.4 Open files: Files (columns) with no pawns on them, making them ideal highways for heavy pieces (ex. Rooks, Queens); These are helpful because Rooks become active immediately when on them, pressure can be applied deep into the opponent's position, and they often lead to invasions on the 7th rank
3.5 Semi-open file: Files (columns) where one side has no pawn on the file (the other does)
3.6 Diagonal / File control: Dominating long lines on the board so your pieces can operate freely while restricting your opponent’s; Key steps: 1) Occupy, 2) Battery, 3) Invade; Tips: diagonals matter more for Open positions, file control matters more for Endgames, and if you control a line, don’t trade without a reason
4. Other Assets
4.1 Extra tempo: Free move or time advantage that lets you improve your position while your opponent must respond or waste time; Get extra tempos with forcing moves (checks, threats, attacks) or making the opponent move the same piece twice
4.2 Opposition: Endgame concept where the kings face each other with one square between them, and the player not to move has the advantage
Direct opposition: Kings face each other on the same file or rank
Diagonal opposition: Kings oppose along a diagonal
Distant opposition: Kings separated by an odd number of squares
C. Positional Liabalities
1. Backward pawns
1.1 Backward pawns: Pawn that cannot safely advance because it would be captured and cannot be defended by neighboring pawns; Pawns become backward when neighboring pawns advance or exchange, the square in front of it is controlled by the opponent and / or it sits on a semi-open file; These are weaknesses because they are fixed targets, often require piece defense (which ties those pieces down), can’t support passed pawns, and are vulnerable in endgames
1.2 Fixed pawns: Pawns that are locked in place and cannot move or easily exchange, usually because they are blocked by opponent pawns; Their lack of mobility can make them easier for attack
1.3 Stuck pawns: Pawns that are locked in place and cannot move or easily exchange, usually because they are blocked by opponent pawns; Their lack of mobility can make them easier for attack
1.4 Isolated Pawns: Pawns with no neighboring pawns to support them; They are weak because they are on Weak Squares by definition, often Blockaded, and can’t create pawn chains
2. Weak vs strong
2.1 Weak Squares: Opposite of a Strong Square; Squares that cannot be defended or controlled by a pawn
2.2 Weak Color Complexes: Set of squares of one color that can’t be defended by your pawns; opponent’s bishops or knights can dominate these squares