I'm sure your coach tells you to castle all the time. She's right. Castling is 99% of the time AWESOME. And sometimes, it's okay to kick things away from your castle with a pawn. But what happens here, where all the dark squares are open? Do you see how white can saunter on in?!
That's right! If black had a fianchettoed bishop in there, it might be a different story. Notice how the material was the same, but the position was different.
What would you do in the following position, to lure black's pawn forward? He hasn't created the weakness, yet, but you can force it!
If you do create a weakness, sometimes you can strengthen it with a piece. (We don't call pawns "pieces"...poor little guys!) For example, if you move your g pawn forward, put your bishop in the little cave. That's called fianchetto and it's a great strategy. Sometimes you can snake a rook along the long diagonal! But nothing is good 100% of the time!
It's black to move and mate in 4!! But you can do it. Just remember, PP on the PP! (Click if that makes no sense.)
Back rank mate! Super! (Did you see that black needed to have his h pawn forward one so he didn't get mated by the queen? Sometimes it's okay to push a pawn forward. You are getting to that place in your chess career where YOU decide when things are safe or not...! )
Ok, here's a tough one. First, threaten mate in one by using a Queen and Rook Battery on the h file. Then, use your other rook to pin the g pawn to the king! It's black to move again.
Now, if white does nothing, black can take on h3! If white tries to unpin, there is still a mate! White has just played Kh2 to get off the g file. Your mate is all forced. Look at all your sacs.
So! We've learned that a castle can be broken into more easily if one of the pawns in front of the king are pushed. If you do push a pawn, maybe to stop a back rank mate, be aware you are also creating a weakness! When you're not sure what to do, try to create weaknesses in your opponents' positions, and strengthen your own.
See you next time!