The Retrograde Analysis Corner

Problem Paradise

No. 22, Apr-Jun 2002

D119 - Andrew Buchanan
Problem Paradise 22, July-September 2002

[8/8/8/8/1N6/2N5/1P1N4/k2K4]

5+1. Mate in 4 moves

[8/8/8/8/1N6/2N5/1P1N4/k2K4]

W120 - Janis Lukasevics
Problem Paradise 22, July-September 2002

[1k6/1P1p4/pKp5/N1PP4/8/8/8/8]

5+4. Mate in 2 moves

[1k6/1P1p4/pKp5/N1PP4/8/8/8/8]

H132 - Hiromi Tsutsui
Problem Paradise 22, July-September 2002

[Kb6/Rp6/p7/8/kPp5/p1p5/3P4/8]

4+7. Help mate in 2 moves. a) diagram b) d2->d4

[Kb6/Rp6/p7/8/kPp5/p1p5/3P4/8]

F128 - Ayako Okaya
Problem Paradise 22, July-September 2002

[1x4xx/6xK/8/8/8/8/8/1x5x]

1+0+6. Six maskmen, 0 moves

[1x4xx/6xK/8/8/8/8/8/1x5x]

F129 - Ayako Okaya
Problem Paradise 22, July-September 2002

[8/8/8/4x1x1/8/3x1K1x/8/4x1x1]

1+0+6. Six maskmen, 3 moves

[8/8/8/4x1x1/8/3x1K1x/8/4x1x1]

R054 - Eric Huber
Problem Paradise 22, July-September 2002

16+16. Proof game in 9.0 moves (Transmuting kings)

[r1b1Kbnr/pp1p1ppp/2p5/2n1p1B1/3P4/Q4P2/PPP1PqPP/RN2kBNR]

R055 - Eric Huber
Problem Paradise 22, July-September 2002

1+2. Retract one move, then hs#1.5

[8/8/8/8/8/8/1K1p4/3k4]

R056 - Rustam Ubaidullaev
Problem Paradise 22, July-September 2002

14+12. Proof game in 28.5 moves

[1rqq1b2/pPPPPPP1/2R2n1n/3Q3p/k7/3K4/bp3p2/1NB2BNR]

Six maskmen, n moves

Identify all of black's six unknowns in n consecutive legal white king-moves, under the following conditions:

The six black unknowns are of different type (P, S, B, R, Q, K are all present exactly once)
The white king isn't in check in the diagram position.
The white king can't capture.
The position is legal.

Examples

in F128, the unknowns can be identified in the diagram position. h1 isn't a rook or a queen, because white isn't in check in this position.
In F129, the first white move can't be Kf3-f2, because no black unknown could be a knight then.

Transmuted kings

When in check, the king moves like the checking piece for one half-move. Example: The game can start with 1. e4 f5 2. Qh5 Kh5 (black king moves like a queen, because he's in check by the white queen).