Check is one of the most, if not the most, important concepts in chess. Check means the king is in danger. This means that the player whose king is in danger MUST get their king out of check.
There are three ways that a player can get out of check
1. Move – This means to move your king out of danger.
2. Block– This means moving a piece in between your king and the piece attacking it. Note: you cannot block a check from a Knight because it skips over pieces.
3. Attack– This means you are attacking the piece that is putting your king in check. You can use your king to attack or another piece on your team.
A good chess player will look through all his/her options before deciding. In each position, the correct move may be to move, block, or attack, but you will never know until you look at all the options.
Take a look at this position, what should the white team do?
What do you think the white king should do. He can move out of the way to b1 or b2. He can also use his queen to block on a2, but the best option is to capture the rook on a7 with the queen on f2.