user1887: To create a weak square it has been suggested to me to force my opponent to make a pawn move: Weak and strong squares. 
How do you do that? Is there a general situation to force a pawn move? Or are there several distinct situations to do that? Most of all HOW do you do it?

user1967: A good example of this is this link Minority Attack
Forcing the opponent to make a move has a popular German word in Chess: Zugzwang, which means move-compulsion.
For a good examination of Zugzwang see Forcing Moves by IM Bryan Smith.
This area is too complex to have a general method for every situation, even if reduced to just pawn moves. 
I think there are some general areas. One should understand Opposition and ideas such as such as mined squares in which one side can force the other to step into the mined square. 

user1856: If a pawn move is absolutely forced, that usually means there's a serious threat that needs to be defended (e.g, loss of significant material, checkmate threat). Commonly, you can provoke pawn moves by piling up pressure on weak pawns, attacking the king or pinning a knight with your bishop. Basically you provoke pawn moves by creating threats; the pawn moves to defend the threat.
As for weak squares, it's only weak if you can use that square to generate new threats, or sometimes to create a defensive blockade. If not then its just a harmless hole in the position (harmless can still be useful though, sometimes your pieces just need a safe square to go to). So before trying to provoke a pawn move to weaken a square, you should also think about what you can then accomplish with that square. If you can't use it, it's not "weak".

user2001: I can think of 4 ways of forcing a pawn forward:

Threaten a pawn
Provoke a pawn to move forward to protect from e.g. a check
Provoke a pawn to move forward to chase away one of your pieces
Create a Zugzwang (en.wikipedia.org/wiki/Zugzwang) that forces a pawn forward


1887: <p>To create a weak square it has been suggested to me to force my opponent to make a pawn move: <a href="https://chess.stackexchange.com/questions/4105/weak-and-strong-squares">Weak and strong squares</a>. </p>

<p>How do you do that? Is there a general situation to force a pawn move? Or are there several distinct situations to do that? Most of all HOW do you do it?</p>
 1967: <p>A good example of this is this link <a href="http://www.chess.com/article/view/minority-attack" rel="nofollow">Minority Attack</a></p>

<p>Forcing the opponent to make a move has a popular German word in Chess: <a href="http://www.chessgames.com/perl/chesscollection?cid=1001725" rel="nofollow">Zugzwang, which means move-compulsion.</a>
For a good examination of Zugzwang see <a href="http://www.chess.com/article/view/forcing-moves-part-1" rel="nofollow">Forcing Moves</a> by IM Bryan Smith.</p>

<p>This area is too complex to have a general method for every situation, even if reduced to just pawn moves. </p>

<p>I think there are some general areas. One should understand <a href="http://www.chess.com/forum/view/endgames/knowing-the-opposition-rules-can-help" rel="nofollow">Opposition</a> and ideas such as such as <a href="http://en.wikipedia.org/wiki/Zugzwang#Mined_squares" rel="nofollow">mined squares</a> in which one side can force the other to step into the mined square. </p>
 1856: <p>If a pawn move is <em>absolutely</em> forced, that usually means there's a serious threat that needs to be defended (e.g, loss of significant material, checkmate threat). Commonly, you can provoke pawn moves by piling up pressure on weak pawns, attacking the king or pinning a knight with your bishop. Basically you provoke pawn moves by creating threats; the pawn moves to defend the threat.</p>

<p>As for weak squares, it's only weak if you can use that square to generate new threats, or sometimes to create a defensive blockade. If not then its just a harmless hole in the position (harmless can still be useful though, sometimes your pieces just need a safe square to go to). So before trying to provoke a pawn move to weaken a square, you should also think about what you can then accomplish with that square. If you can't use it, it's not "weak".</p>
 2001: <p>I can think of 4 ways of forcing a pawn forward:</p>

<ol>
<li>Threaten a pawn</li>
<li>Provoke a pawn to move forward to protect from e.g. a check</li>
<li>Provoke a pawn to move forward to chase away one of your pieces</li>
<li>Create a Zugzwang (en.wikipedia.org/wiki/Zugzwang) that forces a pawn forward</li>
</ol>
