# Advantage of Diagonal Opposition

Suppose there are only two pieces on the board, black king and white king. Black king is at g7 and white king is at e5. It's Black's turn to move. So in this case white has the opposition. Black now plays Kg6.
Can white reach any of the last three squares f8 or g8 or h8. If the answer is "no", then what's the advantage of having diagonal opposition ?

• If only the kings are left on the board then it cannot be "somebody's turn". The game is over when neither side can mate the opponent by any series of legal moves. The game is a draw. Neither side can have an advantage. Your question doesn't make sense. Mar 18, 2018 at 18:43
• Thanks Brian. I know, thats just an assumed position and play to learn about diagonal opposition.
– Abhi
Mar 18, 2018 at 20:01

Diagonal opposition can be thought of as a means to an end. No matter where your opponent's King moves, you can get direct opposition sooner or later. Examples from your position:

1...Kf7 2. Kf5 (White gets the direct opposition).

1..Kg6 2. Ke6 (White gets the direct opposition).

1...Kg8 2. Ke6 Kh8 3. Kf6 Kh7 4. Kf7 (White gets the direct opposition).

As per your question regarding f8, g8, and h8, White could not reach the squares even if he had direct opposition in a similar position. Put White's King on e6, and Black's King on g6 (Black to move). You'll find that Black can defend the 3 squares, despite White having the opposition.

The purpose of opposition is that it forces your opponent to move his King out of the way, letting you pass in one way or the other. Note that the way your opponent moves his King out of the way is up to him, so he could protect f8, g8, h8 indefinitely by keeping his King there. However, that would let your King pass his by playing Kf5, Kg4, Kh4 (and reaching the h-file, if that was your goal).

• I don't have a board to verify right now, but if Black king is on g7 and White takes g5 direct opposition, then White achieves his goal right? Mar 19, 2018 at 20:37
• @ericw31415 If White's goal is to reach f8, g8, or h8 then yes, White achieves it. This is because Black's King has to move out of the way, and White's King can go past. For example, 1...Kf7 2. Kh6 Kg8 3. Kg6 Kf8 4. Kh7 Kf7 5. Kh8 Mar 20, 2018 at 0:04
• Ok yeah, I was thinking about outflanking Mar 20, 2018 at 0:39
• @ericw31415 Yep, opposition is a very useful tool if you want to outflank your opponent's King. Mar 20, 2018 at 0:47

The advantage of opposition can be seen when there is a pawn on the board.

And the point is that Diagonal Opposition can be easily converted to Horizontal or Vertical Opposition which is quite useful.

• Thanks. In the situation I mentioned can white achieve vertical opposition ?
– Abhi
Mar 18, 2018 at 17:32
• Nope, not with nothing else on the board. But, of course, in real life there's always something else on the board.
– D M
Mar 18, 2018 at 17:39
• There is no way to achieve vertical opposition in your example. Mar 18, 2018 at 17:41