Daily chess puzzle: Check Mate #487

Another puzzle from Dragoslav Andric’s 1981 book “Matni Udar”.  
Black to play and mate White

 
Sigurjonsson v Timman, Wijk aan Zee, 1980

Solution

After first trying fancy stuff like 1…Qa4??, I quickly concentrated on finding the follow up to the obvious 1…Rb2 2Kb2.

The choices were between rook check or queen check, but when I saw the idea must be to play Ne2 diverting the Qg4 with …f5 became obvious, and therefore 2..Qb7+ (or b6) became obvious.

FEN 
5rk1/p1p1ppb1/2qp2p1/8/1r1n1PQP/2N3R1/PPPB4/2KR4 b – – 0 1