Zugzwang is the topic I want to discuss today, an idea known for more then 1000 years in chess history. It’s a term used in chess for specific situations where it’s a player’s turn, but any move would worsen his or her position. Van Perlo (2006) describes it for example as "a player to move cannot do anything without making an important concession". The term is actually German and means something like a forced move. In chess games, if you’re in zugzwang, it means you’ll be ending up significantly worse then you would have if it weren’t your turn, usually in the form of getting a draw instead of a win, or even a loss instead of a draw or win. Zugzwang occurs mostly in endgames.
There are many types of zugzwang, and I will discuss a couple of them. I offered most of the examples as puzzles, so that you have more interaction with the board then is the case with mere diagrams.
The most known one is the endgame where one side has only a king, and the other side has a king and some pawns, or a king and a rook. In the endgame with the pawns, creating zugzwang usually means that you win space because the opponent has to move his king away (opposition). With the rook, it results in forcing the king in the corner. You’re probably already familiar with these types of zugzwang, but it’s a good introduction, and maybe necessary for the players unfamiliar to the topic. If you’re already familiar with the theme, you can skip the first two puzzles, because they’re really easy.
Off course, these are the easiest and most familiar situations. A more interesting situation arises when there is a so called "reciprocal zugzwang". This means that you’re in zugzwang, but your opponent as well. Even though its an interesting position, it’s still considered very easy, and one example will suffice. You’ll look at the same game from two perspectives. White to move will be at disadvantage because he’ll draw, and black to move because he’ll lose. If white’s to move black is at advantage, because he has the opposition, meaning that he forces the zugzwang upon the white player by putting the king on a key square, as we’ll see in the example below.
Now the same example, but with black to move:
The last example I want to make before moving on with the real puzzles, is the situation where “trébuchet” arises. It’s an extreme form of zugzwang because the one to move, is the one to lose. White to move loses, but black to move loses as well, because the player who has to move, loses his own pawn.
The one below is even better. Black to move loses to 1...b3 2.axb3#. If it where white to move, he would be losing because he would be allowing b3 by moving his king away.
Now that we had the easy part it’s time to introduce some more difficult puzzles I have found. The oldest example known is dated around 813, and will be the first example:
Another one I really like, is a position made up by former world champion Morphy:
Here’s some puzzle I posted somewhere else already on this site, but it fits really well in this article:
Now, I want to show you a fine example of the losing player forcing a draw by using zugzwang:
What is important to remind is that you knew what to look for in these games. In the real games, these situations may be harder to find for you. I hope that this article made this easier, and that you might be able to draw losing games now, using this information.
For the ones more interested in the topic, I found a game played by no one less then Fischer using this concept.
zugzwang occures in move 33. Bb3. Black can't move the king without losing (...Rxc7 Rxf8). Black can't move the knight, because Be6 will lose the rook to white. Pawns can be moved, but those moves will run out...
Soltis, Andy (July 2009), "Chess to Enjoy: I'll Take a Pass", Chess Life 2009 (7): 14–15