We believe that when two composers try to cooperate, the final result comes more quickly, because both composers work more intensely. The cooperation is a factor of motivation.
In problem-387 the composers are George Georgopoulos and Efthimios Papakonstantinou.
George Georgopoulos & Efthimios Papakonstantinou,
First Prize, Die Schwalbe, 1990,
Mate in 4 moves.
#4 (9 + 12)
If you try to move first the Rook to make room for the Bishop, ( 5 tries : [1.R~? Ba6!] ), the problem will not be solved. With your key-move you must sacrifice the white Queen! Anyway, the sacrifice threatens Mate in 3, and Black can not be indifferent.
Key : 1.Qxf6! ( > 2.Sxg5 Rxg5 3.Qh6+ Rh5 4.Qxh5# )
1...Bxf6 2.Re1 ( > 3.Bf1# )
___2...Ba6 3.Sc4 ( Novotny sacrifice on c4, > 4.Sf4# / Bf1# )
___2...Bxc6 3.Re4 ( Novotny sacrifice on e4, > 4.Sf4# / Bf1# )
1...Sxf6 2.Rb1 ( > 3.Bf1# )
___2...Ba6 3.Rb5 ( Novotny sacrifice on b5, > 4.Sxg5# / Bf1# )
___2...Bxc6 3.Sd5 ( Novotny sacrifice on d5, > 4.Sxg5# / Bf1# )
For the moves 2...Ba6/Bxc6 the White continues with Knight/Rook in one variation, and with Rook/Knight in the other.
(The problem is included in the edition "Selected Chess Compositions by Greek Composers", prepared for the 47_th World Congress of Chess Composition, Halkidiki, Greece, September 4-11, 2004. Editor : Harry Fougiaxis).