Ded. M. Caillaud & N. Plaksin
1st Prize Rex Multiplex, 1983
All captures have been done by P's. Taking back any move by a wP from the West side would entomb the bK behind an unbreakable barrier.
The only way to unlock the position is to take back b6-b7 so that the bK can be extracted from his South prison. This requires first that we drive the bQB back to c8, and that we extract the wK from the f8-h8 squares. The bKR must be in the North cage when we take back b6-b7. The bQB will be uncaptured by h3xBg4 (with the wKR in its cage), but we first need the Rg1 to help extract the wK.
This rook has a long way to go from g1 to a1-a3-b3-b5-a5 to f8 before it can be used to shield the wK from the bRe7. This trip involves delicate crossings with two Bs and the bK.
When the wR eventually reaches the 8th rank, we can extract the bR from e7, so that the wK himself can wait in e7. Then the bR must switch position with the wR: for this, they both have to go out of the cage, taking the long journey. Then the bR can be reinstalled on the 8th rank with the wR as a shield that will allow the wK to wait on b5. Then at last the wR can go back to h1, allowing h3xBg4 to be undone and the whole mess to unlock.
Finally, we see that the last 75 moves (150 single moves) have been without any capture or pawn move (or castling). So that the game is a draw as a result of the fifty moves rule .