[White "Daily tactics #13"]   [Black "Black to play and win"]   [Result "0-1"]   [FEN "r2qr1k1/1p3pp1/1bp1b2p/3n1N1P/6P1/3BN3/1PPQ4/1K2R1R1 b- - 0 1"]   {The point of this combination is to force the Black king on a2 to give the double check. This is accomplished by a double sacrifice:}   1... Ra1+ 2 Kxa1 Qa8+ 3 Kb1 Qa2+!!   {White is helpless}   4 Kxa2 Nc3+{and when the king moves, Ra8+ wins)