[Retros] Fwd: Proof game promotion task

Kevin Begley kevinjbegley at gmail.com
Mon May 10 04:50:05 EDT 2010

Good question, Noam..

There are a few such achievements...

1) the record length PG57.5, (8bR+8wR -- Pronkin & Frolkin),
2) diagonalized promotions (of Caillaud & Heinonen) already sited here.
orthogonalized promotions (Caillaud)
3) Pronkin & Frolkin made a number of others:
-PG45 (4wB+4bB+4bN+3bR in final diagram)
- Pronkin & Frolkin & Goldsteen PG52 (8wR+7bR+3bS in final diagram)
-PG55.5 (8wR+8bR)
-Frolkin PG52 (inexact) 6bB + 3bR
...tons more...

I did quickly skim through a large section of PGs >40 moves, in the
Win Chloe database, and found no problem with 9 units of the same type
& color (however, I may have overlooked something)...

A pattern fast emerges, where it becomes clear that promoted force
in the diagram was deliberately avoided -- even, it seems, if
avoidance made their tasks more difficult (my guess).

So, I suspect most would prefer to attempt the interesting task you
outlined via Ceriani-Frolkin annihilation of 2 promoted units (to
retain a nice diagram).

I am not aware of any technique to directly search for such things
in any PG database.

Finally, I regret some discourteous responses which you encountered here...
...which reads like an outrageous bid for partial credit.


On 5/10/10, joose norri <joose_norri at hotmail.com> wrote:


> Well not obvious or trivial, but uninteresting, apart from the task

> element. I don't like counting promotions or whatever. Is one interestingly

> motivated promotion less impressive than five trivial ones? Clearly I'm not

> quoting my own thoughts.

> Joose



> > To: joose_norri at hotmail.com; retros at janko.at

> > Subject: Re: [Retros] Fwd: Proof game promotion task

> > CC: tchow at alum.mit.edu

> > Date: Sun, 9 May 2010 22:53:18 -0400

> > From: elkies at math.harvard.edu

> >

> > Tim Chow asked:

> >

> > > [...] What is the most number of knights (or queens, or whatever)

> > > to appear in the set position of a proof game [with a unique solution]?

> >

> > Joose Norri responds:

> >

> > > Yes, obviously one could do -- but why!? Sorry, missed the irony.

> >

> > I don't see why this need be ironic or ugly; it looks to me like a

> > legitimate task. And it certainly *doesn't* look obvious that one can

> > promote all White pawns to Bishops in a sound proof game! For starters

> > such a game must have length at least 39.5, and it's already nontrivial

> > to attain such lengths at all, let alone with 40 pawn moves on one side.

> >

> > NDE


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