The Key Question About Key Squares

Please help an old Wizard understand Key Squares.

I have heard youtubers mention key squares.  I have seen some message posts that reference them too.  Books bring them up without ever explaining them.  Silman complains about how people don't notice them.  In some openings I am told a square is a key square and it is important - but I am never told why.

Please reveal some of the secrets of the arcane topic of Key Squares:

1) What are key squares and why are they important?

2) How do you find them on the board?

Please "spell" out the "magic" methods of Key Squares!

I am just a beginner trying to learn but go to lessons and search squares. You'll find what your looking for. Good Luck.

Thanks Micky and Randi. I think I understand the endgame key squares (at least a little), but I am lost on the middle game key squares. I am having a hard time figuring out these middle game key squares. Do you know any books that cover the topic well? I have a box of chess books but I can not find good coverage of the topic.

I think Mickey1943 is exactly right. Mostly I've heard about key squares in endgames. I just did a search and found a few references in books dealing with key squares in middlegame positions, but not many. I don't know any books that deal at length with key squares in a middlegame, but below are some isolated references I found. In the context of middlegame positions the word "key" seems to be synonymous with the general terms "critical" or "in question", whereas in endgame positions the word seems to have a more specific, technical meaning, whereby all the key squares can be generated mechanically, based on the position, usually at squares flanking a pawn that is trying to promote.

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(p. 37)
      GAME SIX
      Weak Pawns, Weak Squares and
      Mighty, Mighty Knights
      H. Mattison . A. Nimzovich
      Carlsbad 1929, NIMZO-INDIAN DEFENSE

It is amazing how much instructive
strategy Nimzovich can pack into
a mere 23 moves.
   His attack on a doubled Pawn
leads to a weakening of a key square.
On this important square Nimzovich
plants a Knight so firmly that it
cannot be dislodged. He then forces
open a file for the benefit of his
Queen Rook. With that sector
under control, he switches the King
Knight over to the center of the
board. The power generated by the
centralized Knights is devastating.
So great is the effect that Mattison
feels compelled to resign, though he
hasn't lost so much as a Pawn.
   Is chess of this sort an art or a
science? In the hands of a crafts-
man like Nimzovich, it may be either.

Chernev, Irving. 1965. The Most Instructive Games of Chess Ever Played: 62 Masterpieces of Chess Strategy. New York: Dover Publications, Inc.

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This game score may be found at:

https://www.chess.com/blog/kramercito/h-mattison---a-nimzovich-carlsbad-1929-nimzo-indian-defense

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(p. 110)
KEY POINTS FOR WHITE TO REMEMBER IN BxH7+ COMBINATIONS

1. Before playing Bxh7+, make sure that Black cannot place a Knight on f6 or f8,
defending the key h7 square. Further, check to see if Black's Queen Bishop can
move from, say, c8 to f5 or, in the case of the Queen, from d8 to d3, defending
the h7 square. In Genlinger-Kashdan, for example, the Bishop went from b7 to
e4 to guard h7.

Alburt, Lev, and Larry Parr. 1997. Secrets of the Russian Chess Masters, Volume 2: Beyond the Basics. New York: W. W. Norton & Company.

https://en.wikipedia.org/wiki/Key_square

You might as well rename "key square" to "important square." It's about as helpful and non-specific as telling a player that to win games you have to find "good moves."

Key squares have some idea or pattern associated with them. You can't expect to find them if you don't know the idea in the first place, and the circumstances that create them are wide ranging, from attack to defense, strategic to tactical, and opening to endgame.

If an author calls something a key square without explaining why, and you have no idea why it's a key square, then I think it's a safe guess that your level is below the author's target audience. I'd put it away and go to a book aimed at your level.

Exactly^. All this chess terminology is rather useless if you don't know what it means.

I've heard if key squares, but I've never used this idea before in any of my games or training.

Yeah, I never think to myself during a game "what are the key squares?"

Why do you say paradoxically?

The pawn structure with d6 and e5 in the Sicilian is pretty well known.

In that line, d5 and some other light squares are "key squares".

But all i think is that I'd like to get a knight there.

Awesome!  Thank you all for your insights.  Thinking of key squares as important squares helps me a lot - the term just resonates better with me.  Ok!  So now when I run into mention of key squares I will ask myself "Why is that square important?"

if we are looking to try and promote this pawn for white then we have to occupy with our king a set of 3 specific squares that lie two ranks in front of our pawn which are b6, c6 and d6. If the king can reach one of these squares then he can force the pawn thru to promotion. If this looks complicated to you then work with the technique involved to do this needs to be practiced. Any beginner endgame book will automatically have this in there because this is at the extreme bottom of basic endgame knowledge. This is pretty much the stuff that you learn first in any pursuit to know endgames

Moreover, almost always when an author or youtuber is referring to a key square in an opening or middlegame position or any position that hasnt been reduced down to only kings and pawns they are meaning an "important square" usually this is a weak square or a square that if they are able to get a minor piece there it will be posted very strong usually in the middle of the board. example