´╗┐ A claustrophobic royal knight hunt


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Paul Valle    (2011-01-08 22:10:46)
A claustrophobic royal knight hunt

In the ChessPosition (see diagram) Black's task is to make consecutive moves and take the White Knight with his King. Black can not move any pawns (and the King cannot move into check). Shuffle a way and find the lowest move count for the capture! Problem from 1874 by the American William A. Shinkman.

a b c d e f g h

Josef Riha    (2011-01-09 00:13:01)
A claustrophobic royal knight hunt

Sorry, but where's the white king? :-)

Paul Valle    (2011-01-09 00:32:29)
A claustrophobic royal knight hunt

There is no White King and White does not move at all. how many consecutive moves do you need to capture the White Knight with the Black King? :)

Philip Roe    (2011-01-09 19:51:45)
A claustrophobic royal knight hunt

Looks to me like 28 moves.

1.Bf1 2.Rg2 3.Kg3 4.Bh2 5.R2g1 6.Bg2 7.Rf1 8.Rhg1 9.Bh1 10.Rg2 11.Bg1 12.Kh2 13.Rg3 14.Bg2 15.Kh1 16.Bh2 17.Rfg1 18.Bf1 19.R3g2 20.Bg3 21.Rh2 22.R1g2 23.Kg1 24.Rh1 25.R2h2 26.Bg2 27.Kf1 28.Kxf1.

Paul Valle    (2011-01-10 02:20:29)
A claustrophobic royal knight hunt

I found it initially astonishing that it took over 20 moves to get there ... You're close Philip, but it can be done in shorter than 28 moves ;)

Svante Carl von Erichsen    (2011-04-03 00:23:17)
A claustrophobic royal knight hunt

I think that one move can be scraped off of Philip's sequence by moving the King instead of the Rook at move 21:

21.Kh2 22.Rh1 23.Kg1 24.Rgh2 25.Bg2 26.Kf1 27.Kxe1

I believe the search tree is sufficiently small to actually prove the solution. There are not many branches.

Ilmars Cirulis    (2011-04-26 18:57:51)
A claustrophobic royal knight hunt

Yes, 27 moves are fastest possible way. I made tablebases for this problem. :D It's even better than search tree, because we have only 90 legal positions. Here is one more solution (so we have multiple solutions): 1. Bf1 2. Rg2 3. Kg3 4. Bh2 5. R2g1 6. Bg2 7. Rf1 8. Bg1 9. Rh2 10. Bh1 11. Rg2 12. Kh2 13. Rg3 14. Bg2 15. Kh1 16. Bh2 17. Rg1 18. Bf1 19. R3g2 20. Bg3 21. Kh2 22. Rh1 23. Kg1 24. Rgh2 25. Bg2 26. Kf1 27. Kxe1 The starting position is the only one with 27 moves to make. Interestingly, did the author also made tablebases or smth similar? :)

Paul Valle    (2011-05-03 23:50:31)
A claustrophobic royal knight hunt

27 moves is correct guys. I don┤t have much info on the problem other than what I have already given. You can find another problem by the author on wiki (the last problem): http://en.wikipedia.org/wiki/Joke_chess_problem