The BDS Website

BDS

The Problemist, 2003

#2
SIREN e2
TRITONs g1; c8
NEREIDEs a2, d6

1.Sd5!  (2.SIc2#)

1...TRc5 2.Sb4#
1...NDc5 2.Sxc5#
1...g3   2.Sf4#
1...f4   2.Se5#
1...e5   2.TRg3#

The wSIe2 guards the wRc4 before the threat as b5 is empty and after the threat as c5 is empty. Black can stop the threat by moving to c5. 1...TRc5 interferes with the bNDd6 and 1...NDc5 unguards c5 by occupying it. The next three variastions show three more interferences with the bNDd6. 1...g3 pins the wSI, but, with g3 now occupied f4 is unguarded for 2.Sf4#. 1...f4 threatens 2...Qd4 after the threat, but unguards e5 for 2.Se5#. 1...e5 threatens to play 2...e4 after the threat, but allows 2.TRg3. Black interferes with the bNDd6 in four different ways, three of them on the one line.