Originals from The Problemist May 2001

a) 1.Rxe3 Rg3 2.Re6 Rxb3#

b) 1.Rxd3 Qf3 2.Rd5 Qxb3#

Line clearance for mating move. First white move is chosen according to square where bR can interfere with bBg8.

1.Bd4 Sxb4+ 2.Sxb4 Rxc3#

1.Qd4 dxe3 2.Sxe3 Sxe5#

Change of pin on d-file. White on 1st move captures black piece guarding the mating square and black immediately recaptures, but for different reasons - in a) it is parrying of check, in b) blocking.

a) 1.Rd4 exf7+ 2.Sce4 Qc1#

b) 1.Be4 cxd6+ 2.Sd4 Qxg3#

Echo diagonal-orthogonal of pin change on the same line.

1.g4 Rxg4 2.Re5 Rf4#
1.Se5 Kg1 2.Be4 Rg3#
1.e5 Rxg5 2.Kf2 Rxf5#
1.Bb7 Bxb7 2.Be5 Bxc6#

4 inteferences arranged on the same square e5.

a) 1.Ra5 Ke3 2.Rc5 Rf5 3.exf5 Bf7#

b) 1.Ra4 Kf3 2.Rc4 Bc5 3.dxc5 Rd8#

White piece from f2 is sacrificed and piece from d8 mates. The model mates are finished by black blocking and guarding of some flights by bK.

a) 1.Bxe5+ Kg8 2.Bb8 Bf6 3.Qc3 Bxc3#

b) 1.Rxd8+ Kg7 2.Rd4 Re8 3.Ra8 Rxa8#

WK moves from check and leaves own remaining line piece pinned. That's why black must unpin it and only after that he can sacrifice the other line mover at mating square. Echo diagonal-orthogonal, but rather brutal for my taste.

a) 1.Sxe4 Rg1 2.Bc4+ Kxb1 3.Kd3 Rd1#

b) 1.Sf4 Bxd7 2.Kxe4 Rxg4 3.d4 Bxc6#

Model pin mates after at least a bit analogous play - bS is pinned during play, white mates along line different from line between its diagram position and mating line. The rest is varying.

1.Rh3? th.2.Rxc4+ Bxc4#
1...Sd2 2.Sc5+ dxc5#
1...Se2!

1.Qe1? th. 2.Sc5+ dxc5#
1...e4 2.Rxc4+ Bxc4#
1...c6!

1.Qxd6! th. 2.Qc6+ Rxc6#
1...Sd4 2.Rxc4+ Bxc4#
1...cxd6 2.Sc5+ dxc5#

White needs to have neutralized Rh4's or Qd1's action to lines f1-a6 and h6-a6. In tries he fails, in solution he succeeds.

1.Qf8! th.2.Bd4+ Kxd4 3.Qc5+ bxc5#
1...Bf2 (Rf2, Re3) 2.Qe7+ Kd4 3.Qc5+ bxc5#
1...Rxd3 2.Rh5+ Kxe4 3.Sxc3+ Bxc3#
1...Bxd3 2.Qe8+ Kd6 3.Sb5+ Qxb5#

For me not very convincing selfmate, first two variations contain the WCCT theme, unity of defence and harmful motivation.

1.Sb6! th. 2.a8Q/B+ Rxa8 3.f8Q/R+ Rxf8 4.Qg4+ Kxg4#
1...h5 2.Sd5! th. 3.Qxe3+ Kg4 4.Qe6+ Kf3 5.Qe2+ Bxe2#
2...Rxf7 3.Qxf7+ Kg4 4.Qf5+ Kxf5 5.Sxe3+ Bxe3#

Wow! As usually by Camillo Gamnitzer... This time I incline to see switchbacks as the main theme: 1.Sb6 2.Sd5 in main line, 2...Rxa8 3...Rxf8 in 1st threat, 3.Qxe3 4.Qe6 and 3...Kg4 4...Kf3 in 2nd threat, it means 4 switchbacks with interesting motivation.

a) 1.Ke6+ Kf8+ 2.Kc8+ Kxc2#

b) 1.Kd6+ Kc8+ 2.Kf8+ Kxe4#

Real transmuting play, super Durbar. Only pity is that scheme is completely symmetrical.

1.Sg2? th. 2.Se1#
1...LEe5 2.c6 th. 3.Sc5#
1...VAe5!

1.b3? th. 2.Sb2#
1...LEe5 2.c6 th. 3.Sc5#
1...PAe5!

1.c6! th. 2.Sc5#
1...PAe5 2.Sg2 th 3.Se1#
2...LEe8 3.Sc5#
1...VAe5 2.b3 th 3.Sb2#
2...LEh8 3.Sc5#

Reciprocal obstructions at e5. In fact it is special form of Dresdner theme involving three black pieces doubled: after try 1.Sg2? there is good defence 1...VAe5!, after key in variation 1...PAe5 2.Sg2 good defence from try is substitued by new black defence 2...LEe8 not present in the try. As all these black moves are played by 3 black pieces, it is Wechselform of Dresdner - I believe. Some logical expert can correct me if I'm wrong, please...