For beginners, it can often be difficult to checkmate an opponent's king even with overwhelming force. Conversely, new players often continue playing long after a game should have already been drawn due to the insufficient mating material rule. Here's a quick guide to what you can (and cannot) use to checkmate an enemy king.
King and Queen vs. King: The stronger side should be able to checkmate easily.
King and Rook vs. King: The stronger side can checkmate, and while it may take more moves than with a queen, the technique is still quite simple.
King and Bishop vs. King: The stronger side cannot checkmate.
King and Knight vs. King: The stronger side cannot checkmate.
King and Pawn vs. King: The stronger side may be able to checkmate, depending on the position. The goal here is to promote the pawn into a queen, after which checkmating is fairly simple.
King and Two Bishops vs. King: The stronger side can checkmate, though the method for doing so is somewhat more complex than with a rook or queen.
King and Two Knights vs. King: The stronger side cannot force a checkmate, although it is possible with the cooperation of the enemy king.
King, Bishop and Knight vs. King: The stronger side can checkmate. However, the technique is rather difficult, and even many strong players have failed to properly convert this endgame, especially in time pressure.
King vs. King: This endgame is always a draw, despite the heroic efforts of beginners and scholastic players who have danced their kings around the board for dozens of moves.
