[Retros] Promotion to knight a must

[andrew buchanan]

Hi Andrey,

Thanks for the nice concept. The one that you suggest can indeed be reduced:

rnb1k1nr/ppp2ppp/3P4/1R2p3/1b2B3/3KP3/PPP2PP1/RNB1nq2
PG in 11.0

The solution is the same as yours until White's 10th, then continues:
10.d5 Bb4 11.d6 e1S#.

A shorter example with a different matrix is:

rnb1kbnr/pppp1p1p/4p3/6Q1/6B1/6PK/PPPP1P2/RNB3nq
PG in 9.0

With any different promotion choice, Black's last two moves may be
transposed. I can't resist saying I like this PG, and (if no one comes up
with a faster one :-) ) would like to dedicate it to you, Andrey.

However, this is all straying a bit from Hirokaz's theme. A knight promotion
isn't really an *under-promotion*. There is still the question of producing
a promotion to R or B which works as a PG, where the promotion to Q has a
single dual.

Cheers,
Andrew.

-----Original Message-----
From: retros-bounces at janko.at [mailto:retros-bounces at janko.at] On Behalf Of
afretro
Sent: 16 December 2006 09:17
To: retros at janko.at
Subject: [Retros] Promotion to knight a must

Hello to all,
Surely this idea can be implemented in a shorter game:
1.Pe2-e3   Pd7-d5   2.Bf1-d3   Pd5-d4   3.Bd3-e4   Pd4-d3   
4.Qd1-e2   Pd3xe2   5.Pd2-d4   Qd8-d6   6.Ke1-d2   Qd6xh2   
7.Kd2-d3   Qh2xg1   8.Rh1-h5   Qg1-f1   9.Rh5-b5   Pe7-e5   
10.Bc1-d2   Bc8-e6   11.Bd2-a5   Bf8-b4   12.Sb1-a3   Pe2-e1=S
Promotion to knight is a must; other promotions destroy game uniqueness (btw
producing only one extra solution resulting from the possibility to
alternate black-s 8th and final moves).
Best wishes,
Andrey
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