The Retrograde Analysis Corner
Miscellaneous Solutions
The position is legal. The white King can reach h7 if the missing wPa2 goes to e6, thereby paralyzing bPf7 and opening the way to the King. Black proceeds similarly.
This requires 4+4 captures. Adding the Bishops which were captured on their home squares, there remain one white and one black free piece, who can (resp.) capture the bPd3 and wPe6 and get captured by the Kings.
2932 - N. Plaksin and A. Zolotarev
Retract -1. Qb8xRb7+ e2-e3 -2. f3-f2 Ba7-g1! -3. Qa8-b8 Bd4-a7 -4. Qb8-a8+ Bf6-d4 -5. f4-f3 Be7-f6 -6. h3-h2 Bf8-e7 -7. h4-h3 f7-f8=B -8. f5-f4 and now
a) -8 ... f6-f7 -9. h5-h4 g5xBf6 -10. Bd4-f6 g4-g5 -11. Bb6-d4 Te5-a5 -12. Ba5-b6+ Re8-e5 -13. f6-f5 e7-e8=R -14. f7-f6 f6xBe7 -15. Bf8-e7 f5-f6 -16. e7xNd6 Ne4-d6 -17. Kd6-c6 Nc5-e4+ etc., or
b) -8 ... g6xNf7 -9. Nd8-f7 Rb5-b7 -10. Nb7-d8+ Re5-b5 -11. h5-h4 Re8-e5 -12. f6-f5 e7-e8=R -13. f7-f6 f6xBe7 -14. Bf8-e7 f5-f6 -15. e7xNd6 Ne4-d6 -16. Kd6-c6 Nc5-e4+ etc.