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MatPlus.Net Forum General Fairy Promotion Convention Question
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(1) Posted by Kevin Begley [Saturday, Jan 8, 2011 03:43]; edited by Kevin Begley [11-01-08]

Fairy Promotion Convention Question

Two questions:

1) Suppose, in a pawns only position, where your goal is AUW, you have a choice...

You can:
a) modify the possible promotions, or
[e.g., modify promotions to allow: Q, R, B & NightriderHoppers, but no Knights.]
b) instantiate the fairy units (allowing their promotion) under the diagram , if the orthodox units play no role anyway.
[e.g., instantiate a Nriderhopper (which does not appear in the diagram), allowing Knight promotions, since they have no affect.]

Which is better (does it matter that the intended theme is: "all-units" promote)?

2) Suppose, in a situation where you have one fairy unit appearing in a pawn-only diagram, and you intend to twin as follows:

a) Fairy Unit in diagram = Nightrider, and
b) Fairy Unit in diagram = Grasshopper.

If the point of your twins is only to establish the promotion possibilities (upon capture of the fairy unit)...

Is there some mechanism needed to exclude Grasshopper promotions from part a), and to exclude Nightrider promotions from part b)?
Or, is it inherently assumed that these should be considered as separate diagrams?

I'm not sure what is the accepted convention here...
I do know that Win Chloe allows promotions to any of the units appearing in any twin phases, whereas Popeye does not.
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(2) Posted by Joost de Heer [Saturday, Jan 8, 2011 14:07]; edited by Joost de Heer [11-01-08]

For 1), I'd say that you should mention below the diagram all extra possible promotions (e.g. 'Promotion to leo allowed')
For 2), The usual rule is that you can only promote to pieces that are present in the diagram. So if there's a nightrider in a) and a grasshopper in b), you can only promote to QRBSN in a), and QRBSG in b). In 'Umwandlungen in Märchenfiguren', the case that in both twins you can promote to QRBSGN is mentioned as extra condition 'Umwandlung auch', and the case where you can promote only to pieces present in the twin-part is mentioned as extra condition 'Umwandlung nur'.
Some examples (all numbers refer to UiM93):

23 Nils Adrian Bakke
Neujahrskarte 1971
(= 2+2 )

ser-=7 durch Schwarz
Umwandlung in Kaiserin erlaubt

139 Erich Bartel
3202 Sw VIII 1980
(= 2+3 )

h=2 Umwandlung nur
a) = Nachtreiter
b) = Camelreiter
c) = Zebrareiter

140 Cyrano
F600v Pst VII 1981
(= 5+2 )

h=2 Umwandlung auch
= Camel
a) c6->c5, = Grashüpfer
b) = Nachtreiter
c) = Camelreiter
d) = Zebrareiter

23: 5. a1=KS 6. KSa5 7. KSb7=
139: a) 1. Ng5 d8=N 2. Nc3 Kc3= b) 1. CRb5 Kc3 2. CRc8 dc8=CR= c) 1. ZRc5 Kc3 2. ZRe8 de8=ZR= (Umwandlung nur stops cooks like a) 1. Nb6 Kc3 2. Nc8 dc8=CR)
140: a) Gc6 Cb5 2. Ge8 de8=G b) 1. Ne7 Cd5 2. Nc8 dc8=CR= c) 1. CRd5 Cb5 2. CRc8 dc8=N= d) ZRa2 Cd5 2. ZRe8 de8=ZR= (b) and c) would be unsolvable with 'Umwandlung nur')
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(3) Posted by Kevin Begley [Saturday, Jan 8, 2011 14:17]

Thank you, Joost!
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(4) Posted by Juraj Lörinc [Saturday, Jan 8, 2011 20:05]

Once upon a time I have judged a tourney with the following problem:

Ivo Lebloch & Bedrich Formanek
Special Commendation Pat a Mat 1991-92
(= 2+9 )

a) nightrider b5
b) pao b5

Given the thread topic, the solution is easy to find:

a) 1.Qa1 g7 2.Rb1 g8=PA 3.Bb2 PAg5 4.Nc3 PAc5=
b) 1.Qb1 g7 2.Ba1 g8=N 3.Rb2 Nxc6 4.PAb3 Na5=

Namely, black promotes to piece that is not on the board in the respective phase.

As a solver of magazine, I had managed to find the solution without any hint and I had felt it to be ok. Then a few years later, as a substitute judge, I was not so sure about conventions, that is why special commendation. Today I would probably go with normal commendation again as in fairy chess everything depends on convention or author's decision, if it breaks convention.
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(5) Posted by Kevin Begley [Sunday, Jan 9, 2011 00:43]

Thanks Juraj -- if your point is that we shouldn't be too judgmental about convention, your point is well received.
Still, it is comforting to measure how far I may be wandering off the yellow brick road. :)
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(6) Posted by Kevin Begley [Sunday, Jan 9, 2011 02:44]; edited by Kevin Begley [11-01-09]

I'm still not clear how best to express one problem... so, maybe this will help:

KB Original, MPF 2011
(= 3+2 )
h=2 .
Chameleon Chess (SBRQ)
b) Reversed Chameleon Chess (QRBS)

Does this imply what I expect it implies?
1) promotions to orthodox units are prohibited by condition, and
2) the Bishop (on b1) is a chameleon-type (which is subordinate to the condition, as dictated by each phase).

Intent: changed fairy-AUW.
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(7) Posted by Joost de Heer [Sunday, Jan 9, 2011 13:24]

The pieces in your example are defined by the fairy condition. In this case it would feel unnatural to me to use 'Umwandlung auch'. It's like saying that in a twin a) orthodox b) Circe, one could choose to have a Circe rebirth in a).
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(8) Posted by Kevin Begley [Sunday, Jan 9, 2011 19:38]; edited by Kevin Begley [11-01-09]


That's how I interpret it too, but it is not completely obvious to me -- I guess I expect the chameleons to appear unorthodox.
For example, suppose I really wanted to add an orthodox Bishop to what is otherwise the Chameleon condition.
Granted, I should probably not use this condition, if that is my intent... I should use chameleon units instead...

I'm brand new... need to check my understanding of basic conventions, from time to time.
I appreciate the help!
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MatPlus.Net Forum General Fairy Promotion Convention Question