I'm not really good enough to post lessons on here but I just played this game against gmh007.
'##, play without chesscomputer ####' he says,
yup he got whupped,
2 games running with the same move, its a good example of mistakes I see defending the castle, particularly; Playing h3 does not protect your castle, it is a point of attack for your opponent, In this game there are 2 mistakes I can see (plus swapping the bishop)
23 h3. This allows me to fork h3 and anything that is on f3, forcing you to swap the pawn and open up my rook. You can also, sometimes sacrifice your bishop against it (as in the first game). Lastly you can hang a piece there guarded by h5, a fishing pole. h3 is to be avoided if possible.
24 g3. This piece is loose! my bishop pins f2, so g3 in unguarded.
These 2 moves were supposed to defend the castle but lost the game.
Belows the first game with a bishop sac on h3 which was not sound but I got lucky 🙂