How to Checkmate with the King

Many people try to get the secret Killer King achievement, yet they have one hurdle in their way. How do they exactly get checkmate with their king? You cannot deliver a check directly using the king!

But what you can do is reveal a check upon your opponent's king by moving your king. Here are the steps to your victory:

1. Obtain a material advantage
2. Have at least 2 major pieces that can move in straight lines horizontally and vertically.
3. Restrict your opponent's king to the backrank (I recommend you use the ladder technique for this step) and don't stalemate!
4. Bring your king to the last rank
5. Put one of your major pieces behind your king
6. Move your king so that it does not obstruct the control of the second last rank and that it reveals a checkmate upon your opponent's king. Since it was obstructed to the last rank and there was a check on the backrank which cannot be blocked, your opponent's king is checkmated with your king!

As soon as you get the checkmate, you will receive the Killer King achievement. Here is an example game:

(I was white in the game)