[Retros] Red-Handed

[andrew buchanan]

Hi Roberto,

Thanks for your mail. Maybe determining criteria is less problematic that I had
thought. I don't know though.

You say that overlooking check is an "opportunity". But overlooking mate is
not? What's your logic there? How about if a player makes a move out of turn?
Or (subtle difference) if a player passes without having moved? After Kf1-g1,
is it an opportunity error to complete the move with Rh1-f1?

I appreciate that the legality of the diagram is not at question for this
format. My remark on proof games was a more general one, in response to the
idea that fairy pieces + pawns =< 8.

I find the terminology "MDR" a little dull. There are too many acronyms in this
little hobby anyway. May I suggest "Red-Handed" as a lively phrase which (in
English) exactly captures your idea?

Andrew.

--- raosorio at fibertel.com.ar wrote:


> 

> Hi Andrew,

> 

> "I have to confess an aesthetic preference for problem forms which are 

> "self-defining". With MDR, it appears that there is a codification required

> for 

> each form as to what "opportunities" and "incompletions" are legitimate. I

> have 

> a related kind of trauma about lexical problems, which depend on the language

> 

> used to record the moves. My problem, sorry. "

> ***************************************************************

> why? perhaps dues to tthe fact the explaining article is missing here.

> Opportunities are well defined ( leaving your king in check, castling when

> you

> had already loose the right to do it, etc) and incompletions are related to

> chess

> moves that involve more than one piece. All these cases have to be deducted

> from the retroanalysis.

> 

> 

> "I think the basic principle should be that the solver is required in

> principle 

> to demonstrate whether any position, even a fairy position, is legal. If the 

> position is legal, then it can be assumed by the solver that it derives from 

> some history (although no reason to assume one history over another). If it

> is 

> illegal, then for a fairy position there is no issue. For an conventional 

> position, it acquires the property of fairiness, but there is otherwise no 

> issue. "

> ****************************************************************

> MDR tries to present the conventional position not as a fairy one but as

> a feseable situation in real game, resulting from a last illegal move

> but under control for the retro rhinking.

> 

> Roberto

> 

> 

> Hi Roberto, 

> 

> 

> >Circe problem. Mate? 

> 

> 

> I think that the intended answer is "No." Black has just captured Na2, which 

> must re-appear like Duncan Idaho on b1 to complete the move and block the 

> check. White's prior move can only have been discovered check. 

> 

> The key question to be resolved in solving the problem was whether you

> intended 

> overlooking check or mate to be a "legitimate" error. The answer is no,

> because 

> e.g. otherwise Black might just have captured B on a2, and the problem would

> be 

> cooked. 

> 

> However this meta-reasoning can now be applied to all other problems of this 

> form, which are therefore easier. 

> 

> I have to confess an aesthetic preference for problem forms which are 

> "self-defining". With MDR, it appears that there is a codification required

> for 

> each form as to what "opportunities" and "incompletions" are legitimate. I

> have 

> a related kind of trauma about lexical problems, which depend on the language

> 

> used to record the moves. My problem, sorry. 

> 

> I applaud the attempt to combine fairy + FIDE rules however. Some fairy forms

> 

> (e.g. Circe, maximummer) naturally admit retro logic all the way back to the 

> game array. 

> 

> Others (e.g. with weird units) do not admit retro logic. We can add the 

> convention that the game is otherwise orthodox, but there are extra options

> for 

> pieces to promote to. That convention is an elegant idea which I hadn't come 

> across before. If it is already widely adopted, or if it formed part of the 

> pre-announcement to the German tournament referred to earlier, then it's 

> totally OK to form part of the judging criteria for this tournament. Not sure

> I 

> would want to see it as a default convention though. 

> 

> The Codex is not very helpful about all this, stating baldly that fairy 

> problems have no history. 

> 

> I think the basic principle should be that the solver is required in

> principle 

> to demonstrate whether any position, even a fairy position, is legal. If the 

> position is legal, then it can be assumed by the solver that it derives from 

> some history (although no reason to assume one history over another). If it

> is 

> illegal, then for a fairy position there is no issue. For an conventional 

> position, it acquires the property of fairiness, but there is otherwise no 

> issue. 

> 

> Best, 

> Andrew. 

> 

> --- raosorio at fibertel.com.ar wrote: 

> 

> 

> > 

> 

> > Hi Guus and everybody, 

> 

> > 

> 

> > "When you think about it, the whole concept is quite similar to MDR but 

> 

> > projected in the domain of typographic and pictographic errors" 

> 

> > 

> 

> > Yes, it is. The MDR convention is an effort to provide an scenario where

> all 

> 

> > the things might be 

> 

> > quite subltle. There is a remarkable potential here (I think that the

> Ke1-g1 

> 

> > problem is a good 

> 

> > example. Ke1-g1 is a geometrically correct move due to the h1 rook. Without

> 

> 

> > this, this king evolution 

> 

> > would not fit with any geometry alllowed by article 3). 

> 

> > 

> 

> > Look at this Werner's problem, 

> 

> > 

> 

> > Werner Keym 

> 

> > Die Welt 1969 (VI) Die Schwalbe 8 04/1971 

> 

> > 1B6/8/4PPPP/4p2P/5k1P/3Q3P/8/6KR 

> 

> > #0,5 

> 

> > 

> 

> > the position contains a very nice retroanalysis, but the stip #0.5 makes

> the 

> 

> > solution evident. 

> 

> > MDR provides the following alternative presentation: (How does this end? 

> 

> > MDR). 

> 

> > 

> 

> > Both theses cases belong to the "finalyzed and incomplete move" cathegory. 

> 

> > After the 7.4 retraction article 4.6 forces to make the complete move (and 

> 

> > then to mate). 

> 

> > 

> 

> > Best, 

> 

> > Roberto 

> 

> > 

> 

> > 

> 

> > Thanks Roberto, I will look at the position. For years I have enjoyed

> solving 

> 

> > the Christmas puzzle in one of our newspapers, for the main reason that

> there 

> 

> > is always one error in it, two in the very good years. Nothing exceeds the 

> 

> > satisfaction of finding the errors plus the solutions! Also, this will be 

> 

> > last fortress to fall to the computer, a million years from now. One year

> ago 

> 

> > I suggested to the belgium team captain to organize a solving contest based

> 

> 

> > on the intentional error idea. I mentioned options like "omitting a pawn in

> 

> 

> > the diagram", "changing draw to win in the stipulation", "mistyping

> helpmate 

> 

> > for selfmate" (this one I encountered in a recent puzzle) - possibly in a

> mix 

> 

> > with some correct presentations as well. For the requirement to be in

> special 

> 

=== message truncated ===