Opposition

What is opposition

The term of opposition refers to the position of the two kings placed one in front of the other separated by a square.

Obtaining opposition is very important in pawns endings and in many cases is decisive.

Look at the following game.

Opposition

The two kings are in opposition. The king who has to leave opposition will loose. 1... Kc7-d7 2. Kc5-b6 Kd7-c8 and with 3. Kb6-c6! the White wins the opposition again. Now we have the same situation as earlier : the black king has to leave the opposition :
3... Kc8-b8 (or Kc1-d1) 4. Kc6-d7 and now the white king has the promotion square under control. 4... Kb8-b7 5. c4-c5 Kb7-b8 6. c5-c6 Kb8-a7 7. c6-c7 Ka7-b6 8. c7-c8 and now White has promoted the pawn into a queen.The black king will inevitable be checkmated.
Now let's take a look to the original position. If the white king has to leave the opposition 1. Kc5-b5 then the black king will maintain the opposition by 1 ... Kc7-b7 2. c4-c5 Kb7-c7 3. c5-c6 Kc7-c8 4.Kb5-b6 Kc8-b8 and the game ends a draw; White has to give up its pawn or there will be a stalemate situation.