[Retros] Article 16 and Ceriani's example

[Valery Liskovets]

A.Kornilov and me in the article "Die partielle Synthese in Retroproblemen",

Die Schwalbe, 1986, h.99, 66-68, interpreted this famous controversial
two-mover by L.Ceriani as a HYBRID stipulated "AL(&PF)" (where "AL"
(ad libitum) is equivalent to "PRA, Typ Keym" and "PF" (post factum) is
similar to "RS"). A TRIPLE retro-relationship: Bl castling [right] excludes
W castling [right] but implies e.p. [right]. I.1.0-0! (0-0-0??); II.1.cxb6+
e.p.!

Valery Liskovets

Rol, Guus wrote:


> [see in the Retro Corner: "Partial Retrograde Analysis" and "Retro

> Strategy" in the modified Codex by Werner Keym, Meisenheim]

>

> Werner Keym presents one of Ceriani's compositions as example 4 in his

> clarification to the new article 16 in the Codex. He makes the point

> that it is self-evident that this problem should be understood as a PRA

> problem rather than an RS problem since the PRA solution includes and

> exceeds the RS solution. I analyzed this problem a few years ago and

> concluded that neither the RS nor the PRA interpretation is

> satisfactory.

>

> Looking at Ceriani from a PRA standpoint we can readily observe that the

> on/off state of the white castling right 0-0 plays no relevant role in

> controlling the "PRA parts". The move 0-0 only serves to avoid the

> knight check in the variation where such is required. This becomes clear

> when you change wPc2 to c4. In spite of the fact that the white and

> black castlings are no longer mutually exclusive, the 2 partial

> solutions remain precisely the same. Instead of changing the Pawn

> position one might also place wKe1 on e2. Eliminating the white castling

> right altogether while simultaneously disabling the potential check

> still delivers the same partial solutions but this time Rf1 replaces 0-0

> in one solution part.

>

> In RS, the opposite is true. Both suggested modifications to the PRA

> setting would make the RS solution fail. The e.p. state, so important in

> the PRA version, cannot be capitalized on (by convention) and therefore

> disappears from the picture. Removing bNa1 and moving wPb3 to a2 (and

> possibly a few other changes) creates a position which illustrates that

> the white castling choice is primarily motivated by the need to apply

> retro-strategy. The check escape is only the duplicate argument here.

>

> The comparison of the RS and RV approach tells us that the PRA solution

> only seemingly overlaps the RS solution. As seen from the previous

> analysis, the vital argument in the RS solution - mutual exclusivity of

> white and black castling rights - has zero significance in the PRA

> solution. The content of the white castling variants in the RS and the

> PRA approach can therefore not be considered "the same" and it becomes

> dubious to justify that Ceriani's problem is "obviously" PRA and not RS.

> Which in turn indicates that Cerinani's example may not be the most

> appropriate elucidation to article 16, clause(3).

>

> Another way to look at it is by conceiving Ceriani's creation as neither

> RS nor PRA. Possibly a twin of both logics, but not a very successful

> one considering the duplicate arguments and one identical key move.

> There are other ways to classify problems like these, and Valery

> Liskovets has made an earlier attempt at that. In due time I will give

> my own view but such is outside the current scope of evaluating the

> match between article 16 and Ceriani's 1960 composition.

>

> Guus Rol.

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