Mat en 4

Les Blancs jouent et matent en 4 coups

(1792 - auteur inconnu)

FEN : 3K2k1/Q5pR/5p2/1qppPRr1/b5r1/P7/1P6/1B6 w - - 0 1

The good choice

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] [SetUp "1"] [FEN "r2r2k1/p4p1p/1p3Q2/5p2/1bbP4/4R3/PP3PPP/6K1 w - - 0 26"] *

White is on the attack. How to proceed now ?
Allocated time: < 1 min.

Fast calculation

Black to play. How many seconds to find the mate ?

Chess tactic

NN - Sarno,S
1993
Black to play. Do you have this pattern in your mind ?