[Retros] Solutions: Christmas Contest 2005 of Stuttgarter Zeitung

[Jens Guballa]

Hello,

here is the resolution of the Stuttgarter Zeitung Christmas Contest
2005. The German original version is available here:

http://www.kaniaverlag.de/htm/Weihnachts2005.html#2

Here is my translation:


75 participants send their solutions, 51 of them made it to the drawing
lot.

Here are the winners:

1st Prize (Philips-television): Horst Kiemele (Leonberg)
2nd Prize (DVD player): Ralf Feest (Holzgerlingen)
3rd Prize (Digital camera): Thomas Lutzius (Stuttgart)



A: Günther Weeth
+---+---+---+---+---+---+---+---+

| q | N |   | k | B |   |   |   |

+---+---+---+---+---+---+---+---+

| b |   |   | p | p |   |   |   |

+---+---+---+---+---+---+---+---+

| K | P | R | P |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   | P | R |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[qN1kB3/b2pp3/KPRP4/1PR5/8/8/8/8]
Who checkmates in one move?

Wrong is 1... Ba7xb8+. It may seem that black has no last move, but
possible is Kc8-d8 and before that wPc7xTb8=N+. Or Kc8xd8 and before
that wPc7xd8. So the correct solution is 1. Rc8++.



B:  W. Keym und G. Weeth
+---+---+---+---+---+---+---+---+

|   |   |   |   |   | B |   |   |

+---+---+---+---+---+---+---+---+

|   | p |   | N |   |   |   |   |

+---+---+---+---+---+---+---+---+

| N |   |   | P | K |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[5B2/1p1N4/N2PK3/8/8/8/8/8]
Add a black king and a black rook, then mate in one move.

Three solutions:
+Ke8, Rd8 and 1. Nc7++
+Kc6, Rb5 and 1. Nab8++
+Kc8, Rd8 and 1. Nb6++. Here black has only one possible last move:
0-0-0.

+Ka7, Ra7 and 1. Nb6 is not a solution, as here black has no last move.

====================================================

Expert contest: Only 6 people did not fail

Among the 48 sender the following people master all puzzles 
and they were not misled by unforeseen traps:

Dietmar Fauth, Norbert Geisler (Munich), Andrej Frolkin (Kiew), 
Hannu Harkola, Olli Heimo, Hannu Lehto (Finland).

The follwing five people missed one partial solution:
Hans Bergmann (Aalen), Jens Guballa (Tamm), Mario Richter (Berlin), 
Klaus Wenda (Wienna), Markus Zehender (Ulm).

Also worth a book prize were the solutions of Norbert Derksen
(Konstanz),  Randolf Eilenberger (Dossenheim), Kurt Lorenz (Marbach),
Rolf Sandau  (Oberstenfeld), Ronald Schäfer (Aalen), Bernd Schwarzkopf
(Neuß),  Nils Empacher, Thomas Lutzius and Rolf Schreiber (Stuttgart).

Here are the numbers of correct solver per problem:
C: 14
D: 11
E: 36



C: Werner Keym
From a position with four pieces it can be shown that on exactly three
light squares no white bishop ever occurred. How many of those positions
exists where EXACTLY THREE PIECES - including both kings - are
positioned on squares of the same color?

Four solutions:

wKb2, bKb4, wPa3, wPg2
+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   | k |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

| P |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   | K |   |   |   |   | P |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[8/8/8/8/1k6/P7/1K4P1/8]
Last move was a2-a3, so a white bishop never occured on a2, g2 and h1.

Similar:
wKb2, bKb4, wPa3, wPc2
+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   | k |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

| P |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   | K | P |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[8/8/8/8/1k6/P7/1KP5/8]
Here the squares are a2, b1 and c2


wKg5, bKg7, wPg2, bPh6
+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   | k |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   | p |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   | K |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   | P |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[8/6k1/7p/6K1/8/8/6P1/8]
Here g2, h1 and h7 were unreachable for the white bishop.

The mirrowed positions (e.g. wKb2, bKb4, wPa3, bPb7) are not correct
solutions as a promoted white bishop may have occupied the square a8 or
g8.

And the final solution "not really surprising for those who know the
problems of Werner Keym" (Schwarzkopf):

wKg8, bKc8, bRd8, pBd7
+---+---+---+---+---+---+---+---+

|   |   | k | r |   |   | K |   |

+---+---+---+---+---+---+---+---+

|   |   |   | p |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[2kr2K1/3p4/8/8/8/8/8/8]
Last move was ... 0-0-0+, so the squares a8, d7 and e8 were never
occupied by a white bishop.



D: Günther Weeth
+---+---+---+---+---+---+---+---+

|   |   |   |   | k |   |   | r |

+---+---+---+---+---+---+---+---+

|   | R | p |   |   | p |   |   |

+---+---+---+---+---+---+---+---+

| P | P |   | P |   | P |   |   |

+---+---+---+---+---+---+---+---+

| r |   | B | P |   | p |   |   |

+---+---+---+---+---+---+---+---+

| P | K |   |   |   | p |   |   |

+---+---+---+---+---+---+---+---+

| p |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   | P |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+
[4k2r/1Rp2p2/PP1P1P2/r1BP1p2/PK3p2/p7/6P1/8]
White retracts three, black retracts two moves. Then white checkmates in
two moves. Defensive Retractor, i.e. black does not cooperate during the
retraction, so he has a choice.

Back 1. Le3xLc5? fails due to ...Ld4xLc5.
The planned solution is 1. Bg1xPc5! c6-c5+ 2. Kc5xPb4 b5-b4+ 3. Bh2xBg1!
(before that: Pf2xXg1=B+).

In this position the castling 0-0 is prevented the retro analysis,
so that 1. Kc5xc6 and 2. Rb7-b8 checkmates.

The position shows that on both sides the pawns have captured five
times, otherwise the bPa3 could not have passed the white pawns.
One white piece was captured by Pf2xXg1=B+, so all eleven missing pieces
are "explained". The white h-pawn has promoted on h8 without a capture, 
so the bRh8 must have moved. The promoted pawn was captured then
somewhere else.

Besides this also the following solution is possible (with some duals):
Back: 1. Bb5xNa6 Nb8-a6+ 2. L~xPc5 c6-c5+ 3. Bc5-~ or 1. Bd4xPc5 c6-c5+
2. Bc5xQd4 Q~-d4+ 3. b5-b6 and in both cases 1. Rb7(x)b8+ Ke8-d7 2.
b5xc6++.

This cook was first reported by M. Richter.

The idea is correctly presented in the follwing position:
+---+---+---+---+---+---+---+---+

|   |   |   |   | k |   |   | r |

+---+---+---+---+---+---+---+---+

| R |   | p |   |   | p |   |   |

+---+---+---+---+---+---+---+---+

| p | P |   | P |   | P |   |   |

+---+---+---+---+---+---+---+---+

| r |   | B | P |   | p |   |   |

+---+---+---+---+---+---+---+---+

| P | K | P |   |   | p |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   |   |   |   |   |   | P |   |

+---+---+---+---+---+---+---+---+

|   | n |   | b |   |   |   |   |

+---+---+---+---+---+---+---+---+
[4k2r/R1p2p2/pP1P1P2/r1BP1p2/PKP2p2/8/6P1/1n1b4]



E: Jens Guballa und Werner Keym
+---+---+---+---+---+---+---+---+

|   |   | K |   | k |   |   | r |

+---+---+---+---+---+---+---+---+

| p |   | p | p |   | r | p |   |

+---+---+---+---+---+---+---+---+

|   |   | p |   |   |   | B |   |

+---+---+---+---+---+---+---+---+

|   |   | Q |   |   |   |   | p |

+---+---+---+---+---+---+---+---+

|   | P |   |   |   |   |   |   |

+---+---+---+---+---+---+---+---+

|   | P |   |   |   |   | P |   |

+---+---+---+---+---+---+---+---+

|   |   | P | P | P | P |   |   |

+---+---+---+---+---+---+---+---+

|   | b |   |   |   |   | B |   |

+---+---+---+---+---+---+---+---+
[2K1k2r/p1pp1rp1/2p3B1/2Q4p/1P6/1P4P1/2PPPP2/1b4B1]
Add a black pawn, then mate in two moves.

+bPa3, 1. Qg5 and 2. Qd8++, because black may not castle anymore. The
white king has no way back to e1 via the queen side, so he must have
come via g6-f7-e7(e8)-d8.

First the wQ has to be retracted to d1, then the wK goes back via d8 to
e1 and the wBg6 retracts to f1. Now the pawn g3 moves back to g2 and the
wBg1 goes to c1. Finally wPb3->b2 and bBb1->c8.

For the sceptict here the evolution of the final position starting from
the initial position:

wPa2xNb3, wPh2-h4, bPe7xNd6xRc5xRb4, wNxPf7, bPb7xNc6, bPh7-h5,
wPh4xBg5-g6xQh7xNg8 (promotion in any piece) ->a3, bPb4xa3,
wPb3-b4, bBc8->b1, wPb2-b3, wBc1->g1, wPg2-g3, wBf1->g8,
bRa8->b6, bKe8->d6, wKe1->d8,c8, bRb6->f7, wQd1->c5, bKd6->e8,
wBg8->g6.


So far the Christmas Contest.



Best regards,
Jens