07/20/2021 (Tue) 18:00:17
Black Rook to E1
Need to take root at E1. Doesn't matter if with queen or rook, so lets say rook.
Black followup with Rook from E8 to E1 to take white's Rook
Need to take rook with Queen
Black Queen to D4
Not checkmate, but white can either block it with queen to F2 or move the king to H1.
Regardless of what happens, it's checkmate eventually.
If white blocks it with the queen, then black just needs to take it, forcing white to move the king to H1, and then it's checkmate when black moves the queen from F2 to F1.
If white just moves the king to H1 right away, then black will move knight to F2, then depending on what white does next, it's either checkmate (moving to G3), or he'll lose his queen (moving back G1, due to black moving his knight to D3, putting white in check while allowing his knight to afterwards take the queen similar to a fork). Unless he blocks with the queen this time on F2, in which case, black will take the queen with their own. This doesn't lead to a checkmate outright, but Black will surely win