Pseudo-carousel change


5 examples for 2nd TT PaM follow. All of them show pseudo-carousel change in set, try and solution and have almost the same motivation. Surely there are some other mechanisms hidden! Please note that 6th problem here contains carousel change and it is not thematical.
Juraj Brabec
3rd Prize Sachmaty 1972

1...Rc5, Bc5 2.Re7#, Sac7#,

1.Sb4? hr. 2.Qd5#, 1...Rf5, Rc5 2.Re7#, Sxc5#, 1...Rc7!,

1.Sc3! hr. 2.Qd5#, 1...Bc5, Rf5 2.Sxc5#, Sac7#









#2 (10+10)

Juraj Brabec
4th HMProbleemblad 1973

1...Be4, Re4 2.Se3#, Qd3#,

1.Re5? hr. 2.Qd5#, 1...dxc6, Be4 2.Se3#, Qxe4#, 1...Rd6!,

1.Rf5! hr. 2.Qd5#, 1...Re4, dxc6 2.Qxe4#, Qd3#









#2 (8+8)

Juraj Brabec
5th Prize Schach-Echo 1973

1...Be6, Re6 2.d7#, S8d7#,

1.Sg6? hr. 2.Qe5#, 1...Qb2, Be6 2.d7#, Sxe6#, 1...Bd7!,

1.Sg4! hr. 2.Qe5#, 1...Re6, Qb2 2.Sxe6#, S8d7#

+++ Composition In the Spotlight (CIS) No. 3 +++

Spotlight comment by Juraj Lörinc:

Change of mates (or more generally continuations) in 3 phases can be boring or interesting. Juraj Brabec was once upon a time one of leading experts for changes in two variations and 3 phases. He told me once that he tries to count all possible different changes of 3x2 variations, including such well known themes like classical Zagorujko (aA, bB - aC, bD - aE, bF), carousel change (aA, bB - bC, cA - cB, aC), change and transferrence in 3 phases (aA, bD - aB, cD - aC, dD) etc. Surely there is more than 100 such thematical complexes...

Looking at the difference between pairs of phases is the best way to identify isomorphism of themes even if they are written in different fashion. That's how he found out in 70s of 20th century that there are in fact two different themes under common sign Z-32-33. Details see at older announcement page. Among the problems from seventies, I think, the present example is the nicest.

In set play, Se5 guards c6, that's why white can cut e8-c6 line at d7, mating after black Grimshaw at e6. Both try and key unguard c6, but the try closes h6-d6 and the key h3-d7. After try, the mate 2.d7# is possible only after opening of other white line to c6, it is a6-c6 by 1...Qb2, what is called "theme B1" or "Somov". On the other hand, defence 1...Be6 removes the second guard from e6, it means Sxe6# can follow. Defence 1...Re6 doesn't exist. After key, the situation is analogical to that after try. The mate 2.Sd7# is possible only after opening of other white line to c6, again theme B1. On the other hand, defence 1...Re6 removes the second guard from e6, it means Sxe6# can follow. Defence 1...Be6 doesn't exist.

Up to 2nd TT PaM the pseudo-carousel theme was shown in orthodox form only with the mechanisms including Grimshaw like here.









#2 (12+8)

Jevgenij Gavrilov
2nd Prize Memorial Kajev 1991

1...Re5, Be5 2.Qd4#, Sdc5#,

1.Sg7? hr. 2.Rd1#, 1...c2, Re5 2.Qd4#, Sxe5#, 1...Rb5!,

1.Sg5! hr. 2.Rd1#, 1...Be5, c2 2.Sxe5#, Sdc5#









#2 (8+12)

Alexandr Pankratev
Europe Echecs 1994

1...Re3, Be3 2.Sd2#, Bd3#,

1.Bf4? hr. 2.Re4#, 1...Re7, Re3 2.Sd2#, Sxe3#, 1...Rd3!,

1.Bg3! hr. 2.Re4#, 1...Be3, Re7 2.Sxe3#, Bd3#









#2 (10+11)

Alex Casa
Werner Speckmann

1st Prize Die Schwalbe 1954

1.Re8? hr. 2.Qf3#, 1...Sc5, Sd6 2.Bf6#, Be5#, 1...Sd8!,

1.Re6? hr. 2.Qf3#, 1...Sd8, Sc5 2.Be5, Bf8#, 1...Sd6!,

1.Re5! hr. 2.Qf3#, 1...Sd6, Sd8 2.Bf8#, Bf6# (1...Sc5 2.Rg5#)

This is carousel change, not thematical for 2nd TT PaM!









#2 (9+5)

Comments to Juraj Lörinc.
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