All combinations can be divided into 4 types: Mate, win material, promotion and drawing.
Winning material is the largest and most diverse category. There are 3 ways material can be won. (1) The moving player has power on an opponent piece than the defender. Examples of attacker to defender ratio are: 1-0, 2-1, 3-2 etc. (Sometimes the attacker has less force, but the defender has more to lose if more valuable pieces are captured.)
The mover may have more power because: (1) The moving player threatened the piece last move, and the opponent allowed it.
(2) The defender just moved the piece there. It is either the result of an immediate blunder (missed THREAT as in (1) or OVERSIGHT as in (2)) or the opponent has a reason for sacrificing.
(3) It may be forced because of one of two reasons: (1) piece cannot move and is tied down because it is pinned, tied or trapped, so when it is attacked, it can't run away. (2) There are attacks at 2 or more points and the defender can't defend all and something must give.
EXAMINE LINES TO EDGES OF BOARD A useful tip is to examine lines of bishops/queens/rooks all the ways of the ends of the board, even if there are pieces of either side in the way! This helps to find many potential dangers, including pins, skewers and discoveries. To have a piece (especially a king or a queen) on the same line as an opponent’s pieces is in itself a disadvantage. Many weaker players don’t look further than where a piece is blocked.
Recognizing positions to terminate search in ('quiet positions'), is a useful skill.
Combinations may happen more often in barren positions than you think. The young Ian Rogers had a well developed skill of unearthing tactics in barren positions. No matter how experienced you are, there may be a theme in the position you are not familiar with, though it can still be discovered with static analysis or BRUTE FORCE. You need to be open to new ideas.
It players learn direct tactics first, planning etc. comes later
COMBINATION A sound combination is a series of forcing moves that checkmates or wins material etc. against best defence. A drawing combination may lead to perpetual check or stalemate.
TRAP A combination which works only if the opponent plays a bad move, or `falls for it.' If the opponent finds the right reply then setting the trap has simply wasted time. Traps can sometimes be justified in a desperate situation, where if you are going to lose anyway, they may be the best practical chance.
UNSOUND COMBINATIONS This is combination which fails against the correct moves. Either the combiner was risking that his opponent would not find the best defence or he made an oversight or miscalculation.
POWER Determining whether a capture can be safely made or not depends in part on the numbers involved. The values of the pieces involved also needs to be taken into account.
VARIATIONS AND SUBVARIATIONS A potential series of moves starting from the current position is called a variation. A potential series of moves starting from somewhere within a variation is called a subvariation.
BRANCHES A variation may consist of as few as one branch or may have many branches of subvariations. A single branch variation may be quite long, while a multi-branch variation may be quite short.
FLEXIBILITY The notion of keeping as many options open as possible.
THREAT A move which prepares a combination. If the opponent's next move does not stop it, the threat may be carried out the very next move.
FORCING MOVE A forcing move is a move that greatly limits reasonable replies. In order, forcing moves are: Checks, mate threats, captures (in order of value of unit captured) and positional threats. Except for the first case, there is an increasing chance you will be able to ignore the threat.
CHECK There are potential ways to escape a check. (1) Capture the checking piece. (2) Move the king to a safe square. (3) Block the check (if by queen, rook or bishop) A check is on a rank or file (queen or rook), diagonal (queen, bishop or pawn) or by a knight.
CHECK: MEETING WITH CHECK Sometimes a check can be met with a check. This can happen if the checking piece is captured, and the capturing piece gives check. The king moves away, discovering a check. A piece blocks the check AND gives check or discovered check. Failure to see a check that meets a check can be disastrous.
CHECK: WHEN TO GIVE Remember the saying "Patzer sees a check, patzer gives a check." If you have a spare check, which does not lead to anything concrete, using it might simply drive your opponent's king to a better square. Only give a check if it improves your position and/or worsens your opponents. A spare check may be more useful later and the opponent may lose a tempo avoiding it.
MEETING THREATS If checked, you have to escape check. You have to stop a mate threat or make check. If you don't regain material, you will be material down. If you don't stop a positional threat you may have a disadvantage in position.
DEFENCES The 3 possible ways of meeting a check (capture, obstruct, run) also apply to other types of threats as well. escape, ignore, direct defence, counterattack multipurpose defensive moves
SAVES A save is a way of escaping from a combination. Any type of combination has a potential 'save'. For example, there are saves against forks, pins etc.
QUIET MOVE Sometimes there is a `quiet' move which refutes a combination. Computer programs tend to be very good at finding tactical moves which are captures for checks, but not so good at finding quiet moves in the middle of a combination.
Combinations which don't work in one move order may work in another. It is rare that the move order doesn't matter. You cannot will a combination to exist. Combinations are present due to one or more weaknesses.
ELEMENTS The first step is to recognize the elements in a position that make a combination likely and the next step is to calculate concrete variations. Great accuracy is needed in playing combinations. For example, whether a pawn is on a2 or a3 may determine whether a combination works or not.
FORK A fork is when a piece moves and attacks 2 or more things at once. If one piece moves away, then the other may be taken. Sometimes the defender can defend by moving one piece and defending the other. Rooks, bishops or queens may fork on the same line or different lines. Every type of piece can fork.
PSEUDO FORK A pseudo fork is when 2 pieces are attacked, but one piece is guarded. It may be as effective as a normal fork. Pseudo forks will be classed with forks.
ROOK AND BISHOP FORK A rook or bishop usually forks on the same line. A rook generally forks on 2 different lines as a result of a capture.
QUEEN FORK It is very easy for the queen to attack 2 or more units at once, but often these attacks are ineffective unless the units are undefended.
KNIGHT FORK A fork by the knight is the most effective because neither forked piece can defend by capturing the knight, unless it is a knight. A fork is the knights main tactic. A family fork is when a knight forks more than 2 pieces. A threat of family fork means that moving 1 piece away will still mean 2 will be forked. 2 knights can sometimes fork in 1 spot.
PAWN FORK A pawn fork is the most dangerous ,but it is fairly difficult to achieve because of the low mobility of the pawn. Rooks and knights are the pieces most vulnerable to attacks by pawns. A pawn may advance with gain of tempo, then fork the next move. A pawn may be sacrificed to decoy pieces to forkable squares.
SAVE FROM FORK One piece may escape and defend the other. Usually not helpful if it is a pawn fork. One piece may escape with a threat.
KING FORK Happens only rarely, due to the king's short range and the inability of the king to take a defended piece. More frequent in the endgame.
FORK OTHER A forking move may be preceded by one or more checks, exchanges, sacrifices or attacking moves. A fork may be combined with other types of combinations.
PIN Pins occur on a rank, file or diagonal. A piece between a queen, rook or bishop of one side and a stronger piece of the same side is pinned. The stronger piece can be called the screened piece.
ABSOLUTE AND RELATIVE PINS A pin to a king is ABSOLUTE as the pinned piece cannot move at all (unless it can move on the same line it is pinned on). Any other pin is RELATIVE. Although in general, this pinned piece cannot move without that side losing material, some surprising counter combinations arise from a relative pin. Sometimes a pinned piece can move on the line it is on.
BUILDING ON A PIN A pinned piece need not be captured right away. The piece will not run away. It may pay to bring more force to build on the pinned piece.
UNPINNING There are several ways in which a pin can be broken. (1) The pinning piece may be driven away or captured. (2) The line between the pinning piece and the pinned piece may be blocked. (3) The line between the pinned piece and the screened piece may be blocked. (4) The screened piece may move away. (5) The screened piece may be defended. (Only sometimes useful.)
SELF PINNING A self pinning move is one which leaves you with a pinned piece where none existed before. Bad in itself, but may be good for other reasons.
ALWAYS UNPIN Always unpin is a good maxim, as a pin is ALWAYS a negative feature of your position, as 1 or 2 pieces have restricted mobility and a later combination may be possible. Whether to unpin immediately depends on the priorities of the position.
DOUBLE PIN A double pin is a pin in which a piece is pinned on 2 different lines. This reduces the chances of survival of the pinned piece. Pinning a piece of the same type is usually not dangerous, but is if doubly pinned.
CROSS PIN Sometimes a pinning piece can be pinned itself.
HALF PIN When there is a potential pin, sometimes a player has one less defender than appears.
ROOK PIN A rook unaided can pin pawn, bishop or knight. A defended rook can pin rook or queen.
BISHOP PIN A bishop unaided can pin pawn, rook or knight. A defended bishop can pin bishop or queen.
QUEEN PIN A queen unaided can pin pawn, bishop, knight or rook. A defended queen can pin a queen. A queen can pin rooks on diagonals and bishops on ranks and files.
OTHER PINS A pinning move may be preceded by one or more checks, exchanges, sacrifices or attacking moves. A pin may be combined with other types of combinations.
SKEWER This may happen on a rank, file or diagonal. A skewer is a pin in reverse. The stronger piece screens a weaker piece from attack. When it escapes, the weaker piece is exposed to capture.
ROOK AND BISHOP SKEWERS An unaided rook or bishop can skewer a king and any other piece. A defended rook or bishop can skewer a queen and any other piece.
QUEEN SKEWER An unaided queen can skewer a king and any other piece.
SAVE FROM SKEWER Sometimes the skewered piece and move and defend the rear piece.
OTHER SKEWERS A skewer may be preceded by one or more checks, exchanges, sacrifices or attacking moves. A skewer may be combined with other types of combinations.
NET A piece that cannot safely move is vulnerable to attack and capture. Checkmate is a form of a net.
PAWN NET Pawns are the most immobile form of unit and often cannot move to escape an attack.
KNIGHT NET Knights in the corner or near the edge are much more likely to be trapped.
BISHOP NET Bishops in the corner or near the edge are more likely to be trapped. Bishops are often trapped by pins.
ROOK NET A rook is usually much harder to trap than a minor piece. A successfully trapped rook is often restricted by its own pawns.
QUEEN NET The queen is the hardest piece to trap but can be vulnerable, especially near the corners.
KING NET A net of the king is of course ,checkmate.
ESCAPE FROM A NET Escaping a net is very similar to escaping from check. Sometimes a counterattack will allow the piece to escape.
DOUBLE ATTACK A fork is when one piece is attacking 2 or more pieces and is one type of double attack. Double attacking can be where 2 pieces attack 2 (or more) pieces each. Discoveries are types of double attacks. A double attack may happen when a player leaves a piece en prise and places another en prise.
DISCOVERIES A discovered check is when a unit unobstructs a queen, rook or bishop , so the latter attacks something. A discovery can be a very powerful type of move, particularly when the moving piece has a threat as well.
DISCOVERED ATTACK A discovered attack (or check) is when a unit unobstructs a queen, rook or bishop, so the latter attacks something.
KING DISCOVERED CHECK Sometimes moving the king may lead to a check. This may allow the situation of meeting a check with a check.
SEESAW Sometimes a discovery is set up in such a way that checks can be repeated while the attacker makes captures.
DOUBLE CHECK A double check is a discovered check in which the moving piece gives check as well. The only way to escape a double check is to move the king.
USELESS DISCOVERIES If a discovery is possible, every move of the moving piece should be considered. Some discoveries are ineffective though, and sometimes they can safely be allowed.
TIES Always untie is a good maxim in the same way that always unpin is. A tied down piece is always a disadvantage in itself. Sometimes, allowing a piece to be tied down may be the best move for other reasons. In general, defend with a pawn where ever possible, or at least defend with the less valuable unit.
REMOVAL OF THE DEFENCE There are several ways in which a tied piece can be exploited. These includes undermining, overloading and simply capturing the defending piece. Capturing the defending piece may involve a temporary sacrifice.
UNDERMINE Attack and harass a defending unit and hence `undermine' its support for whatever it was defending.
OVERLOAD A piece cannot defend 2 or more points and can be overloaded.
CAPTURING THE DEFENDER Capturing the defender may be a straight exchange. In some cases it may be a temporary sacrifice.
PAWN TIES A defending pawn can be undermined by an exchange or by an attack with a pawn.
KNIGHT TIES The knight is the weakest defender ,because it cannot move at all without abandoning its defence. Sometimes the knight can retreat by threatening a fork threat.
ROOK AND BISHOP TIES A rook/bishop can move on the same line and still defend on point. A rook/bishop defending points on different lines cannot move and maintain its defence. The less squares the defending rook/bishop has on the same line of the defending piece, the weaker it is.
QUEEN TIES The queen has many squares it can defend from, but it is exposed to attack. A queen can often defend several points and maintain defence of at least 2 of them.
KING TIES A king is very vulnerable to deflection as it must immediately escape check. A king can sometimes move and maintain defence of 1 or 2 points.
SUMMARY OF WINNING MATERIAL All pieces can fork or create a net. Only line pieces (queen, rook, bishop) can discover, pin or skewer. Any piece can assist a line piece with a discovery. To create a tie combination, 2 pieces (of any type) must work together.
IN BETWEEN MOVE or ZWISCHENZUG An in between move. For example, rather than make a predictable recapture, a different move is played before the recapture, sometimes with dramatic consequences. Types: (1) Check. (2) Capture elsewhere. (3) Attacking move.
X-RAY When a piece defends a friendly unit on the same line, despite an opposing piece being in between them. The defending piece x-rays the opposing piece.
DESPERADO A desperado is an unusual type of combination in which 2 pieces of each side are en prise. A player refrains from capturing his opponents piece and captures with his `desperado' piece instead. In some cases a player makes a desperado capture instead of moving an attacked piece.
DESPERADO QUEEN A desperado queen is very dangerous, as it is very likely o be able to take something effectively.
DESPERADO ROOK OR BISHOP Tends to be straight forward.
DESPERADO KNIGHT Possibly the most common of the desperadoes because of the ability of he knight to jump other pieces.
DESPERADO PAWN These are generally the easiest desperadoes to work out, due to he limited choices of the pawn.
SACRIFICES A sacrifice may be done for all kinds of different reasons.
SACRIFICE FOR TIME A sacrifice may gain a vital tempo (or more) for an attack.
SACRIFICE FOR A OPEN LINE A sacrifice may open a vital line (or more) for an attack on the king.
SACRIFICE: INTERFERENCE A combination which involves obstructing the line of defence between 2 pieces.
SACRIFICE: DECOY This involves tempting an opposing unit (often a king) to a square where a combination can then occur.
SACRIFICE: DEFLECT This involves driving a piece away from the vital defence of a unit or square.
PREPARATORY MOVES The main move of a combination may be preceded by some kind of prepatory move. For example, checks, captures, and tempo attacks. Themes can combine in different ways, e.g./ a fork may be followed by a skewer.
SQUARE CLEARANCE A move that vacates a square, may allow that square to be used for a combination.
LINE CLEARANCE A move that clears a diagonal, rank or file, may allow that line to be used for a combination.
ADVANCED TACTICS There are many types of clues in a position that might indicate a combination is possible. Some cues are pinned pieces, tied pieces, pieces in a net, unprotected pieces or insufficiently protected pieces that can be attacked, a king or queen on the line of an opponent queen, rook or bishop, attacks with pawns, squares on which a fork can take place and promotion possibilities.
TACTICAL ERRORS In a game there are many types of mistakes possible. A mistake may have dramatic consequences - a sudden mate may be allowed, or a piece may be lost for nothing. A mistake may be very minor and have little or no bearing on the outcome of a game. A mistake may create an opportunity for the opponent, who may exploit the mistake or miss the opportunity.
Mistakes can be divided into tactical and positional. Tactical mistakes are usually of greater significance. A tactical mistake may allow a SOUND combination by the opponent who then gains in material or begins a decisive attack on your king. Another mistake is to play an UNSOUND combination which backfires when the opponent defends correctly.
Tactical mistakes can result from failure to recognize an important element (or elements) in a position. Moves such as checks and captures, pins, tied pieces etc. need to be examined. For example, missing one important check by the opponent might render your whole combination unsound.
Tactical mistakes may result from not looking deep enough in a position. (This varies a lot from position to position.) or from not looking around enough. The second is generally the more important of the two. Sometimes all the tactical elements have been recognized, but there is a misunderstanding in how they interact. A mistake may result from an error in understanding or judgment.
There are many mistakes of all kinds in a game. after making a mistake, play as though nothing has happened. The player who makes the second last blunder wins.
Recognizing tactical dangers can reduce the chances of a tactical error. Unprotected pieces or pawns, the king or queen being on the same line as an opponent pieces, pinned pieces, tied pieces, pieces with little or no mobility or pieces that are easily attacked are all potential trouble.' It is good to eliminate these negative features of your position whenever possible.
All games are eventually decided by a tactical melee. A good approach is to consistently strengthen your position in readiness for the inevitable storm. Even if you cannot see all the eventualities of such a melee, if your pieces are on the right squares, your survival chances are increased.
A good technique to help tactical errors is to visualise the position as though you have made your considered move. Does it allow a combination by your opponent? A little time here can prevent many blunders.