[simonreiff]

Interestingly, many people will refer to zugzwang when one player only has losing moves and would love to skip their turn altogether, but that's not zugzwang. As a non-example of zugzwang, consider the position with White having a Kb6 and Rc6, and Black just has Kb8. When White moves 1. Rc5, killing a move, Black has no choice but to move 1...Ka8 followed by 2. Rc8#. However, Black is not in zugzwang, because the position is not mutually bad for either player. As a true example of zugzwang, consider the example where White has a Kf5, pawn on e4, Black has a Kd4 and pawn on e5. Now this position is zugzwang because whichever player has to make the next move loses defense of their pawn and with it, the game. For instance, if it's White to move, the game could continue 1. Kf6 Ke4 2. Kg5 Kf3 3. Kf5 e4 and Black will simply march his e-pawn to the 1st rank, promote to a Queen, and checkmate shortly after.

[T0Bi]

Wikipedia disagrees:

"There are three types of chess positions: either none, one, or both of the players would be at a disadvantage if it were their turn to move. The great majority of positions are of the first type. In chess literature, most writers call positions of the second type zugzwang, and the third type reciprocal zugzwang or mutual zugzwang. "

You're talking about mutual zugzwang

[simonreiff]

The Wikipedia article goes on to say that other authors describe the second type as a "squeeze" -- I think Kemp uses that term -- and only the mutual or reciprocal kind as a true "zugzwang". I can't remember if it was GM Edmar Mednis or IM Rafael Klovsky who told me many years ago that it's only the mutual scenario that qualifies as a "true" zugzwang, but I'm pretty sure it was one or both of them. Either way, the subject has divided chess authors almost since inception of the term in the first place. You can see the Wikipedia article on Immortal Zugzwang, for instance, which is one of the earliest famous examples of "zugzwang" and is featured in Nimzovitch's classic treatise "My System", and at the same time, many other famous players like IM Andy Soltis and others disagreed with the use of the term for that game.

A great article with some really beautiful examples of zugzwang is: https://www.chesshistory.com/winter/extra/zugzwang.html. There's a very nice discussion at the end as well of a disagreement along just these lines as to what truly constitutes zugzwang, between Hooper and Myers.