What Makes a Draw?
Perpetual Check
An important variety of a forced repetition is perpetual check. A perpetual check is a series of checks the king cannot escape from. Usually, the player who keeps on giving checks has to do it, otherwise he or she would lose the game.
First step to discovering perpetual check is looking for it. You have to realize that the opponent's threats or superior forces will win the game unless you act now. Putting his king in check will delay his plans at least for one move.
If you have a choice between different checks, use the one that keeps your opponent's king from escaping and doesn't allow his/her other pieces to come and help. In the above example White wisely refused to take the g5-pawn with check, because that would allow the black king to move out.
Perpetual check doesn't become certain until we have established the pattern of checks and defenses that will repeat itself. In its simplest form, such as the example above, the checking piece and the king go back and forth between two sets: Qg6-Kg8 and Qh6-Kh8.
Now try this one