Black plays and wins in 2 moves https://lichess.org/6INMwwuX/black
1... Kc6 2. Ra1 Qf8#
The analysis board does checkmate in 5 moves, removing the rock first
1...Kc6 2. Kb8 Qb3+ 3. Kc8 Qxd1 4. Kb8 Qb3+ 5. Kc8 Qg8#
Source:
https://www.amazon.com/Chess-Puzzles-Advanced-Expert-Level/dp/B0917YQZP1
