(from TD 100)  by Václav Kotešovec 
Hybrid problems with cyclic change of mates
by Václav Kotešovec, FIDEmaster in composition 1996
In hybrid problems there are identical positions A and B, but stipulation is changed. Interesting results are achieved with specific fairy elements.
Diagram 1 Michel Caillaud Mat 1982

Prototype of hybrid cyclic change in a twomover is a problem diagram 1 by Michel Caillaud. Show solution Brilliant idea. Mates with capture of black pieces are not possible in circe for a check by transferred pieces to white king. Far from it, the mates are delivered on squares no more under black's control and the capture of mating pieces is impossible in this case for a check to black king. Keys in A and B are identical. (See another problem by same author in the FIDE Album 198082 / 875). 
Diagram 2 František Sabol After Michel Caillaud Šachové umeni 1986/4

Diagram 2. In this version the keys are different, which is, in my opinion, better. Show solution 
A joint work diagram 3 by Israeli composers have not an orthodox phase, but it exploits differences between "PlatzwechselcirceQuot; and "normal" Circe. Four white nightriders Nb1, Nh7, Ng4 and Ne1 guard squares c3, d5, e3 and d3. Same white men are redeployed on different squares after moves of black G's and in PWC white controls squares c3, d5, e3 and d3, whereas after same moves in circe there are squares d5, e3, d3 and c3. Very harmonic mechanism.
Diagram 3 Shlomo Seider & Theodor Tauber 1 PR e.a. V. Feenschach 1983

Show solution 
Following three problems are examples of hybrid with other fairy chess elements.
Diagram 4 Václav Kotešovec 4 PR Probleemblad 1990/1

Show solution In orthodox chess Ge5 guards square b5, Gh3 square a3 and Gf8 square a8. In mars circe the G's work from squares e1, h1 and f1 and do not guard the squares b5, a3 and a8. 
Diagram 5 Václav Kotešovec Pat a Mat 1999/26

Show solution In orthodox chess moves of black pieces intercept lines of 3 black grasshoppers f1, f6 and a3 to squares c4, c6 and e7. In Madrasi moves 2. c4+, 2. Bxc6+ and 2. Sxe7+ are not mates, because black can paralyse these pieces after 2.  cxb5!, 2.  Be8! and 2.  Sg6! (See my other Madrasi problem in FIDE Album 198688 / G102). 
Diagram 6 Václav Kotešovec Šachová skladba 1999/66

Diagram 6. In "Kölner kontakt Schach" moves with capture of black rook are not possible because, after that, white queen does not have a neighbour. Moves of black rook enable moves of the queen on other squares but the rook cannot take the white queen for the same reason. Show solution In B after 1.  Rg4 not 2. Sxb7? for Kc4!, and after 1.  Rd4 2. Sxb7#, because the move 2.  Rd6 is in Köko impossible. (See my other Köko problem in 3199 PHENIX 76/1999). 