The most common ways that a chess game might be drawn is the lesson of the week for my beginning students. Examples from practical play are provided as well.
In a chess tournament, players get one point for a win and zero for a loss. When the game ends in a draw, the players split the point for the game: each gets ½ point.
How do games end in a draw?
There are several ways that a game can end in a draw. These are the most common.
Players may agree to a draw, usually because they realize that neither has a reasonable chance of winning. Draw by agreement is rare among scholastic players, as it should be.
When the player on move is not in check and has no legal move, the game ends in stalemate.
Black is in stalemate in this position from a scholastic tournament.
Black to move
Note that if it were White's move, Qg6# is checkmate. This sort of stalemate is far too common in youth events when children do not know possess elementary checkmate skills (see "Cutting Off" for one important aspect of these skills that contains links to other useful posts).
A game that I played this morning had the possibility of ending in stalemate, but ended drawn by agreement instead.
White to move
Black has just promoted a pawn to a new queen, but White gets rids of the queen quickly.
58.Nc3+ Kb2 59.Nxb1 Kxb1 60.Kc3 Ka2
Had Black played 60...a4, I would have played 61.Kb4 and taken the pawn on the next move. That would result in a draw by insufficient material (see below).
61.Kc2 a4 62.Kc1 Ka1 63.Kc2 a3 64.Kc1 Ka2 65.Kc2
I offered a draw here, which my opponent accepted. Had Black played 65...a2, Kc2 would leave Black with no legal moves.
A common error that beginners make is thinking it is stalemate because a king cannot move without considering the other pieces on the board. For stalemate to occur, a player must have no legal moves. Sometimes the only way to win a position is to deprive the enemy king of movement in order to force another piece to move.
In the next position from Barcza – Rethy, 1953, it is not stalemate. The Black king has no legal moves, but the Black pawn does.
Black to move
Black must play 1...c2. White then responds 2.Nc6. Then Black must play 2...c1 and promote the pawn. Because White's last move shield the king from check should Black choose a queen or rook, 3.Nb6# is possible.
When the same position (all the pieces on the board) has occurred three times with the same player to move each time, a draw may be claimed.
In the example from my game this morning above, my opponent and I could have shuffled our kings back and forth until we had reached the same position three times, then either would have been able to claim a draw.
4. 50-move Rule
When 50 moves have passed with neither a capture nor a pawn move, the player on move may claim a draw. White and Black move = one move.
"Max Judd's Draw Claim" describes an entertaining game where a draw was claimed by this rule, but was ultimately rejected. The rule has changed a little bit over the years, and it was somewhat confusing at the time this game was played.
5. Insufficient Material
If neither player possesses enough material to deliver checkmate, the game is drawn. Two lone kings, or a lone king against a king and minor piece (bishop or knight) are insufficient material.
Learning from the Championship Match
The advanced students played chess while also watching game 5 of the World Chess Championship on the demo board. As the game concluded while we had still ten minutes remaining, we quickly examined why the final position forces a draw.
White to move
An opposite colored bishop endgame results from the forced trade of rooks. As Black's bishop guards the promotion square for White's passed pawn, neither side has any reasonable hopes of progress.
*Game four also was drawn after 94 moves.