Pins in Chess
A pin is simply a technique in chess where you trap one of your opponent’s pieces in front of another of their pieces, usually of high value or indeed the king. Similarly to forks, there are broadly 2 types of pins, absolute pins and relative pins. The difference between them is once again whether or not they involve the king. A pin, in general, is where you attack your opponent’s piece with a high-value piece (or king_ behind it). The piece is said to be pinned in front of that piece, since moving it would either be illegal or risk losing a high-value piece. Due to the line of attack nature of pins, it’s not possible for pawns, kings or knights to execute pins, since these do not attack lines along the board.
Absolute pins
An absolute pin is where you trap one of your opponent’s pieces in front of its own king. According to the rules of the game (check these out in our beginner’s guide), you cannot end your turn with your king in check, so if you attack your opponent’s piece in front of your opponent’s king, that piece is effectively pinned in front, meaning it cannot move out of the way or else the king would be under attack. The term in front here is of course relative to the piece that is doing the attacking and where it is on the board. To make this clearer, let’s see a few examples.
Here the white rook is pinned on b2 by the black bishop on e5. The rook cannot move or else it would leave the king in check, which is not allowed. Unless white can escape from the pin, black will be able to take the rook on the next move.
Let’s see an example involving rooks doing the pinning.
Here the black rook on d5 is pinning the white queen on d2 to the white king. Once more, this is an absolute pin since the queen cannot legally move - she could move towards the rook or even take the rook, but she cannot move to the side as doing so would leave white in check, which is not allowed. Unless white can escape from this pin, the black rook would be able to take the queen on the next turn.
Let’s finally take a look at the queen pinning a rook.
Here we have the black queen pinning the white rook. Once again, the rook cannot move or else the king would be in check.
Relative pins
A relative pin is one which does not involve the king. The piece that is pinned is sitting in front of another piece and is therefore pinned. The piece behind the pinned piece is typically a high-value piece, like the queen or rook (or more info about what makes the queen and rook high-value, check out our post on piece values in chess) and can therefore be a useful move to take your opponent’s piece and gain a material advantage in the game.
Since a relative pin does not involve the king, your opponent has a choice as to what they will do in the situation. Move the pinned piece or leave it in place to be taken. There are other options, which we’ll dicuss later in the section on how to escape from a pin. The key is that the choice to move the pinned piece is there, which is why this is known as a relative pin.
Let’s see a couple of examples to demonstrate this idea a bit more clearly.
Here we have a black rook pinning the white bishop in front of the white queen. Clearly, if white moves the bishop, black would be able to take the white queen, making this a relative pin. This sort of scenario often occurs when a player captures a piece (in this example with the bishop now on b5) and is then pinned on the next move as a result. In fact, leaving opportunities like this open for your opponent is exactly the kind of trap that a more advanced player would do in the hopes that their opponent does not notice. The following moves in this scenario would likely be by black trying to attack the bishop and white trying to defend it. If we imagine that black has a pawn that it can advance to attack the bishop, then white is now in trouble. Either they lose their bishop or they move it and lose their queen. Neither option is particularly good.
Let’s see another example:
Here we have a black bishop pinning a white rook in front of the white queen. The rook cannot be moved or else the bishop would be at liberty to take the white queen. White’s best option, if they cannot escape from the pin entirely, would now be to trade the rook for the bishop - since the queen could take the bishop after it has taken the rook.
Aside from absolute and relative pins, there are two more descriptions of pins - partial pins and situational pins.
Partial pins
Partial pins can refer to either relative or absolute pins, but where the pinned piece is also able to move along the line of attack of the pinning piece.
If we look at the previous example, but with a bishop in place of a rook, this is a partial pin, because the white bishop can move and still be pinned to the queen. This provides the obvious advantage that the white bishop could take the black bishop and remove the pin situation. In other scenarios, it could be beneficial for the pinned piece to move to another square where it is protected, ensuring a recapture of the pinning piece, or preventing capture altogether.
Situational pins
Situational pins are where a piece is not pinned in any particular piece, but rather a square or range of squares that would give an advantage to the opponent. An extreme example of this would be a checkmate, although any other advantage, material, positional, or otherwise would qualify.
This may not be so obvious, but here the white bishop on g5 is being situationally pinned in front of the square g1. That’s because if the black rook were to move to g1, then it would result in a checkmate, so even though there is no piece on g1 to protect, the black bishop must protect the square itself or risk losing the game.
Escaping from a pin
Now that we’ve seen what the different types of pin are, let’s take a look at some things to keep in mind when trying to escape from a pin. These vary depending on whether the pin is relative or absolute.
Escaping from either type of pin
The following techniques will work to escape from either type of pin:
- capturing the piece doing the pinning
- move another piece in between the pinning piece and the pinned piece
- protecting the pinned piece
The first and most obvious escape from a pin is to capture the piece doing the pinning. If that piece is unprotected, then the pin was initially not very successful. If the piece is protected, then this escape comes with a few caveats. Firstly, is the piece that can capture the pinning piece of lower or equal value to the pinned piece. If you’re sacrificing your queen to save a rook, that’s not a very sensible choice. Another thing to consider is whether or not the piece protecting the pinning piece can also perform the same pin. Let’s see an example of this:
Returning to our previous example, if we add a single pawn in there then the escape becomes quite simple. Moving the pawn up from e2 to e3 would block the black bishop and successfully remove white from the pin.
Protecting the pinned piece can be effective if it has a lower value than the pinning piece. So if your rook is being pinned by your opponent’s queen, protecting that rook does enough to escape from the pin, since your opponent won’t want to sacrifice their queen for a rook.
Escaping from absolute pins
To escape from absolute pins there is one other move that might be possible, depending on the situation. The move in question only works for specific scenarios, which usually occur towards the end of the game when the board is more open and the pieces have moved around more. It involves threatening another of your opponent’s pieces with the king. By moving the king to within a square of one of your opponent’s pieces, you may be able to force your opponent to abandon the pin and save that piece. It requires the move from the king to be in a way that removes your pinned piece from the pin. Let’s see an example to make it clearer:
Here have black pinning the white rook. The rook cannot move because it is defending the king. However, if white moves the king to g1, it puts pressure on the black rook and also removes the white rook from the pin. In this way, black might decide that a trade is not the right option and abandon the pin. If black goes ahead and takes the rook anyway, white can recapture the black rook, making it an even trade of rooks. The pin wasn’t exactly a failure, but it wasn’t as effective as black had hoped.
Escaping from relative pins
Aside from the moves mentioned previously, there are a couple more ways to escape from a relative pin:
- checking the opponent with either the pinned piece or the piece behind the pinned piece
- threatening a high-value piece with the pinned piece or the piece behind the pinned piece
Checking the opponent is always a good idea when in a tough situation and in the case of a pin, it’s a very useful move to have available. A good opponent will not leave that option available, but if it’s possible, moving either of the pieces in the pin to check your opponent’s king can be an effective way of escaping from the pin.
Looking at an example from earlier, if we include the king on the board, then the escape from the pin becomes clear. Moving the rook up to f7 would check the king and force black to get out of check. With the next move, the white queen could save itself from the attack of the bishop. Indeed, if the black bishop is unprotected, the black queen would be in a position to capture the black bishop - this would constitute what’s known as a discovered attack, where moving one piece out of the way creates an attack with a piece behind. More on this in another post.
This works in a similar way with threatening a high-value piece but more things must be taken into consideration. Whether or not the piece you use to attack the high-value piece is protected, whether the piece you leave behind is protected, whether your opponent’s high-value piece is protected and whether the pinning piece is protected, the relative values of the pieces involved are all important factors. This is a bit arbitrary to read, so let’s see an example to clear it up a bit.
Here we’re switching the black king with the black queen from the previous example. Moving the white rook to f7 now doesn’t help the situation too much. It means that black can either now choose to trade queens (black bishop takes the white queen and the white rook takes the black queen) or better yet, black can gain a material advantage by capturing the white rook leaving the bishop behind to be taken by the white queen. Black loses the bishop (3 points) and gains a rook (5 points) giving themselves a clear advantage in the game. You can read more about this in our article dedicated to piece values.
Changing this example a little more and adding in some protection for the black bishop, it’s clear that this escape would simply not work for white.
Now, it makes little to no sense for white to move the rook to f7. Since the black bishop is protected, black can quite easily take the rook with the queen and white would be foolish to trade the queen for the bishop, seeing as the bishop is now protected.
Executing a pin
In order to execute a successful pin, the previous points need to be considered. If you leave your opponent an easy escape from the pin, then it may not be successful (against less-skilled opponents who do not see the escape, it could still work!), so it’s important to always make sure to keep high value pieces in a protected place, or to ensure that the pinned pieces cannot be moved into secure places to attack them. Executing an absolute pin is generally easier, since the escapes are fewer and there is generally a greater chance of success.
It’s important to note that queens can only ever be partially pinned, since they move in every direction, so if trying to pin a queen, bear in mind that the pinning piece must be protected, or the queen is just going to take it.
Pinning knights along any line (diagonal or rank/file) is easy because they have no possible to move to extract themselves from the pin, just as pinning bishops along rank/file and pinning rooks along diagonals tend to work well, since the pinned piece has no move to make at all.
Pinning with bishops can be a very effective way of gaining an advantage since bishops have a relatively low value (3), meaning that even if your opponent protects the pinned piece or offers up a trade with the piece behind, it’s usually good to sacrifice a bishop for another piece, such as a rook or queen.
If you have any comments, feedback or questions about anything in this post, leave them below.