Kostas Prentos

Original Retro & PG problems
JF – R2017-18

Definition: (click to show/hide)

No.1338 Kostas Prentos

original – 21.10.2018

Solution: (click to show/hide)

white Bf1c1 Ke1 Qd1 Ph2g2f2e2d2c2b2a2 Sg1b1 Rh1a1 black Bf8c8 Ke8 Qd8 Ph7g7f7e7d7c7b7a7 Sg8b8 Rh8a8

PG 11                                       (11+10)

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Paul Rãican
Paul Rãican
October 23, 2018 11:51

Looks like multicolored fireworks. What about two more Q promotions?
12.Be2 dxe2 13.Sc3 exd1=Q [a1,c2=b][d6,h5=w]+ 14.Sxd1 cxd1=Q [a1=w][d6,h5=b]+ 15.Rxd1. The sequence [5.gxf8=Q [h6,f7,g8=w]++ … 13.Sc3] was checked by Jacobi v0.5.3 in about 50 min.

Paul Rãican
Paul Rãican
October 23, 2018 12:10
Reply to  Paul Rãican

This last version quickly demolished when I verified the last 5 moves: 10.Kxg1 dxc2 11.Sd2 Bg4 12.Sb1 cxb1=S 13.Rxb1 Bxd1 14.fxg8=Q [a2=b]+ Kxg8 15.Rxd1

Paul Rãican
Paul Rãican
October 23, 2018 12:22
Reply to  Paul Rãican

But if the very last promotion is a Rook, then we have a unique sequence:
10.Kxg1 Bg4 11.fxg8=Q [g4=w][a2=b]+ Kxg8 12.Be2 dxe2 13.Sc3 exd1=Q [h5,d6=w][a1,c2=b]+ 14.Sxd1 cxd1=R [a1=w][d6=b]+ 15.Rxd1.

Kostas Prentos
Kostas Prentos
October 23, 2018 13:52

Although it may be possible to achieve more than 5 Queen Schnoebelens in a Masand proof game, having spent several days testing and correcting cooked versions to reach 4 and eventually 5 such cases, I realized that it was not an easy task, at all. Based on all the difficulties I experienced, I didn’t even consider going further.

Is it possible that Paul’s suggestion is sound? Just by looking at the final position, I find it extremely unlikely (the diagram in 14.5 moves can almost be reached in an orthodox massacre PG). Of course, it is practically impossible to test similar positions, even with all the progress made by Jacobi. Common sense is the best guide in this case.

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