Of course you should castle. I'm sure your coach has told you to do it 100 times! Castling does protect your king, but not forever! Sometimes it is worth it to give up a piece in order to open up the king. Only sacrifice if you actually SEE a checkmate (or that you will win material or something better) in the future. You always need back up if you sacrifice, so double check your checkmate! Once you are a master you can sacrifice for fun.
In this first puzzle there are two possible ways black can respond to your sacrifice. I will show you the first one.
Example: White to move and win. Use a queen and knight checkmate.
Now you try!
1. White to move and win. (Same first move!)
2. White to move and mate in two. All knight moves! Sac one knight, because you have another!
3. White to move and blow open the kingside with a big sacrifice!
4. White to move again. This time you can give up your queen and watch the knights give checkmate by themselves!
5. White to move. Get the king into position for a Swallow's Tail Mate by sacking your rook.
How did you do? Sacking is a whole lot of fun, right? Just be sure you've calculated clearly, or it's just a lost piece! See you next week!
CIAO!.....