Today, it is black to move. Is it possible to win? What is the plan? How should black proceed?
This is from the GM Le Quang Liem vs GM Peralta at Gibraltar Chess Festival.
You have to win the pawn- you do this by driving the rook away from the 7th rank. I would start with the check from c6:
If white plays 2.Rb6, then 2....Qa4+ allows black to play 3......Kxd7. Continuing:
This move keeps observation on c7 so that the rook can't go there safely, any pawn move loses to Kxd8., and any rook move off the 7th rank except for Rb6 loses the pawn to Kxd7. So.....
If white plays 3.Rb6, black just pins the rook with 3.....Qd4 winning the pawn on the next move. Continuing:
This is a waiting move that keeps c7 under observation again- white is getting more and more constrained......
If white tries 4.Ra7, black just checks from h8 and white can take take the pawn with the king after 5.Kb7. All other moves lose the pawn on the next move. Continuing:
4...........Qa5 5.Kb8 Kd6!
Black has d8 covered by the queen, c7 is still out of play for the white rook, and 6.Ra7 will just lose to Qd8+ followed by loss of the pawn. Continuing:
Of course, 6.Kc8 loses quickly to Qa8+ followed by Qc6+ and Qxd7#. And as before, 6.Ra7 loses the pawn to Qd8+. Continuing:
Not really sure the best line at move 6. Of course, there is work still to be done here to win after the pawn falls, but the white king is already trapped on the edge and near a corner, so I think the win is probably not more than 20 moves from this point, and likely less than 15.