No. 199, February 2003

11783 - **Alexander Yarosh
**Die Schwalbe, No. 199, February 2003

Variation of Die Schwalbe #11584

12+10. Retract 13 half-moves for a position in which it can be proven that black can no longer castle. (Proca retractor)

[5KQ1/3prp2/4pRRk/5prb/P5p1/pP6/P2PPPPP/8]

11784 - **Guenther Weeth**

Die Schwalbe, No. 199, February 2003

(Correction of Die Schwalbe #11652)

12+10. Retract 13 half-moves for a position in which it can be proven that black can no longer castle. (Proca retractor)

[2b5/1p1pp3/4kpp1/p7/7p/1N2P1PP/RP2PrP1/2R1BB1K]

11785 - **Christoph Fieberg**

Die Schwalbe, No. 199, February 2003

14+14. Proof game in 14.5 moves

[rnB1kBnr/p1p1ppqp/8/8/1P4P1/b2P3R/P1P1PP2/RNbQKb2]

11786 - **Joost de Heer**

Die Schwalbe, No. 199, February 2003

8+14. Proof game in 15.5 moves

[rnn1k2r/p1pp1ppp/4p3/8/7b/8/4b3/QKBNRRNB]

11787 - **Reto Aschwanden**

Die Schwalbe, No. 199, February 2003

13+14. Proof game in 19.0 moves

[2k5/pp4pn/7n/3ppr2/6bp/rP5q/Pb3PPP/RNBQKBNR]

11788 - **Wolfgang Dittmann**

Die Schwalbe, No. 199, February 2003

6+8. Retract 29 half-moves for a #1 (Proca retractor, Anticirce Cheylan)

[7q/pp3r1P/1pb5/3P4/k7/p1P2R2/P7/4K3]

11789 - **Bosko Miloseski**

Die Schwalbe, No. 199, February 2003

16+16. Proof game in 14.0 moves (Circe)

[rn1qkbnr/1ppppppp/bp6/1B6/8/8/PPPPPPPP/RNBQK1NR]

11790 - **Wladimir Chutornoj**

Die Schwalbe, No. 199, February 2003

4+3. h# in exactly 4 half-moves; how many solutions? (Vertical cylinder, free castling)

"free castling" on a vertical cylinder: Move the king two squares
on the 8th

rank, and then hop with the rook over the king in either way, if possible.
I.e.

there are four possible castlings in the diagram position; the position
after

those castlings are Kc8/Rb8, Kc8/Rd8, Kg8/Rf8, Kg8/Rh8.

[r3k3/7R/4P3/4B3/8/8/8/5bK1]

11791 - **Alexander Jarosch
**Die Schwalbe, No. 199, February 2003

/This problem was later found to be cooked. See 11791v)

10+10. Last 9 half moves?

[K4rk1/2pp1ppp/1Ppp4/2R5/2PP1Q2/3p4/P1R1P1P1/8]

11792 - **Alexander Jarosch**

Die Schwalbe, No. 199, February 2003

(This problem was later found to be cooked. See 11792v)

6+12. Add both kings in such a way that one side can mate in 1.

[8/2p5/1P6/bPr3p1/pPp1p3/r2p3p/P7/2nRN2n]

11793 - **Klase Kiesow
**Die Schwalbe, No. 199, February 2003

16+15. Proof game in 3.5 moves

[rn1qkbnr/ppp1pppp/3p4/8/4P3/8/PPPP1PPP/RNBQKBNR]

11794 - **Klaus Kiesow**

Die Schwalbe, No. 199, February 2003

15+16. Proof game in 4.0 moves

[rnbqkbnr/ppp2ppp/3pp3/8/8/1PP5/P2PPPPP/RNB1KBNR]

11795 - **Alessandro Cuppini**

Die Schwalbe, No. 199, February 2003

3+7. #4 (Maximummer since black's last move)

[r3k3/6pp/4K2P/4p1b1/8/p3P3/8/8]

In 11784, a possible tactic could for instance be to reach a position
in which

white retracts castling, leading to a position where castlings are mutually

exclusive.

11785-11787 and 11793-11795 are C+. 11790 has more than 170 solutions.