Check is an action in poker when a player decides to pass the current round of betting. According to the rules of poker you can only play Check if you’re the first to make an action in the current betting round, or if no one before you had made any bets/raises.

To make a check in poker means to continue the game without any additional bets from your side. After the check action moves to a player sitting on the left from you, and you are having an option to make a fold, call or raise in future (if any of your opponents makes a bet after your check).

For example, you are playing at the table of NL200 ring game. You are sitting on the big blind position in this hand ($2), and during the flop betting all players have made a call of $2, thus equating their bets with yours. When it will be your turn to act, you will be able to make a raise, raising the bet, or either make a check and take a look at the turn card.

Check is a passive action, which often gives a sign of weakness.

Check in poker is used in the following cases:

• With an aim to take a free card, or with a reason to fold your cards if any of the opponents will make a bet after you;
• When a player is unsure in his cards, and because of that he’s not ready to risk a part of his stack (oftentimes in those cases check is played with an intention to call a bet from an opponent);
• Check with an intention to play check-raise, to lure as many as possible chips from the stack of your opponent. That kind of trick is used when you have a strong combination and you are sure, that your opponent will oftentimes attach your weakness (check).

Example: I haven’t hit the flop and was thinking if I should make a continuation bet, but decided to play check.