Threefold Repetition:

When the same position is reached with similar player to move three times during a game, either player may immediately claim a draw. The procedure for claiming this draw varies somewhat between rule sets, but the rule is fairly standard across the board. This rule exists to end games in which both sides are easily repeating moves.

Most importantly there's no actual rule that allows players to claim a draw by perpetual check. However, the threefold repetition rule (combined with the next type of draw) covers this eventuality; if one player is landing checks again and again with no way for their opponent to escape, they will eventually repeat the same position three times, forcing a draw.

The Fifty-Move Rule:

The fifty move rule is one of the least understood rules in chess. The rule essentially states that if no progress is made after fifty moves by both players, the game is asserted a draw. Progress is determined by the capture or any piece, or even the movement of the pawn. If fifty moves by each player are made without either of these events occurring, either played may claim a draw.

Insufficient Mating Material:

If neither player has enough material remaining to checkmate another, then the game is immediately a draw. Examples of insufficient mating material include a single bishop or even a single knight. In some rule sets, this rule can't be invoked unless it is literally impossible for the opponent to be mated after any sequence of legal moves; under those rules, two knights do count as mating material, just like many other positions where one side could possibly control themselves into a checkmate.

Efforts to Reform Draw Rules:

Many top chess players, fans, and chess officials have tried to find ways to reduce the number of draws in chess - often with the goal of making chess more appealing to spectators. One solution has been to reduce the scoring incentive of draws. For example, some tournaments use "football" scoring for their standings; while players normally receive one point for a win and a half-point for a draw, these tournaments award three points for a win and one point for a draw.

Most other efforts have been aimed primarily at decreasing the frequency of agreed draws, particularly at higher levels of the game. Some chess tournament use rules in which players are not allowed to accept draws before a certain point in the game, such as the 30th move. Another suggestion has been to either remove the draw offer entirely, or to require all draw offers to go through a tournament director or arbiter, who would be empowered to require the players to continue playing if he felt there was any life left in the position.

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