Hi kids! Since you are all such great dancers with the king and queen, now you are ready to learn the king and rook checkmate. It's amazing that all you need is one king and one rook to force a checkmate to happen, but it's true! Do you want to learn how?
One rook, two rook, red rook, blue rook...
First, let's look at our final checkmate position. What should white play?
Rooks are great at back rank mates because they can guard an entire rank, or horizontal line on a chessboard. They can also guard files. Do you know the word for up-and-down lines?
So the king and rook mate works a lot like the queen dance because they will slowly make the box around the king smaller and smaller and smaller until... CHECKMATE!
Think of the king as a dog running loose in your neighborhood. He is pretty cute, but you can't exactly tackle him, so you create an invisible fence around him, until he gets in his own yard (with parent supervision, of course). Your dad will be close by in case you need him to block the giant Newfoundland from escaping.
Basically, we need dad. Step one: get your king and rook together.
After Rd8, you are doing two things: 1) You and dad are teamed up; and, 2) you have already made a box around the king! Do you see it?
The pattern is simple: Ask yourself one question, "Can I make the box smaller (safely)?" If so, move your rook, if not, move your king. That's it! Notice, NO CHECKS! Sometimes just running around checking the king all day is pretty boring. In fact, it's probably going to be a draw if you just say check, check, check...and never checkMATE. It's like you and the dog are having a face off, and you get in front of him, but then he runs to the side. So you get in front again, AH HAH! but then he trots to the other side. Pretty soon, you're going to get tired.
Instead, use your king and rook together. Can you make the box smaller?
So, you bring in your rook so the box gets smaller. If you can't bring in your rook because you would get tackled and lose it or you would make check, then bring in your king! Dad is good at blocking giant dogs.