Chess Terms


Hard to say at first and even harder to spell, what is prophylaxis in chess? Read on to learn more about this key strategic chess concept.

What Is Prophylaxis?

Prophylaxis is seeing what your opponent wants to do and stopping it ahead of time. It's a fairly subtle concept, as sometimes you might prophylactically prevent something that doesn't actually matter. As players improve, one thing they get better at is telling a serious threat apart from an empty one.

Prophylaxis was a key element of the hypermodern theory of chess, spearheaded by Aron Nimzowitsch and Richard Reti.

Yes, him again.

Why Is Prophylaxis Important?

Chess is not just about what you want to play. You also have to pay attention to your opponent's plans. But prophylaxis is more than just stopping immediate tactical threats like checkmates or forks. It's about preventing such threats from being made in the first place.

Beginning players need to worry about hanging pieces and other immediate threats, but as you get better, prophylaxis becomes increasingly important.


The Petrosian Variation of the Queen's Indian Defense is a good early game example of prophylaxis. White plays 4.a3 in order to stop Black from playing ...Bb4+. The idea is to develop with 5.Nc3 next and control the e4 square without having to worry about an annoying pin.

Another type of prophylaxis is when a player gives "luft" to the king by playing h3 or ...h6 to prevent back rank checkmates.

In this oversimplified example, checkmate wasn't threatened yet, but White just played h3 to prophylactically prevent any future checkmates should the white rook leave the back rank. Black can do the same next.

For a final, more complex example, we go to this game from the 1990 World Championship. GM Garry Kasparov's knight on e4 was pinned to his rook on e1. Kasparov didn't care so much about that, but about the fact that ...Qxe1, if GM Anatoly Karpov could play it, would be a check. And so...

(See our article "The Greatest Waiting Moves By Grandmasters" for more on this game and other examples of prophylaxis in action.)


Now you know what prophylaxis is, why it's important, how to spell it, and have seen some examples of prophylaxis in action. Study more on this theme with our Lessons.

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