# A Stranger (Chess Sliding Puzzle)

A suspicious stranger lurks in the village. Deal with him before escorting the King to the luxurious safety of h8.

White is first to move. Only legal chess moves are allowed. Pawns are not promoted on the final rank, nor are they removed.

Use as few moves as possible.

You can post your solutions in quasi-algebraic notation. For example, moving the pawn from b4 to c5 could be notated as Pb4c5 or b4c5 or just b4. You could also post your solutions as animations.

(Click on the image for a virtual board.)

• The problem seems equivalent to the two chess sliding puzzles of the past week after the first move. The only legal moves for the initial state are taking with b4, d4 or e4. Nov 29 '16 at 18:38
• In this puzzle, the option to take with b4, d4, or e4 allows the puzzler to choose which blank square he gets to start with—that dynamic is new to this puzzle. But other than that, it's just like the others. Nov 29 '16 at 18:49
• Puzzle does not explicitly state that we can't let the stranger move first. Just that we have to deal with him before moving the king. Letting the stranger go first could free up several spaces, potentially making the puzzle much easier. Nov 29 '16 at 20:53
• @user3294068, good point, I'll correct this to point out that white must move first. Nov 29 '16 at 20:54

# 60 Moves

We want to move the knight on b6, and will later benefit from an empty c4. One way to do this is with a capture-retreat. 1. Nxc5 2. Nc5e4 3. c5 4. Nc4 5. Ba7b6 6. Ra7 We begin an awkward process of shuffling the king and bishops along the dark squares. We'll need to use a rook if we're going to fill a8. 7. Ra5a6 8. Ba5 9. Bc7b6 10. Bb8c7 11. Kb8 12. Ra8 13. Ba7 14. Bc7b6 15. Kc7 16. Ba7b8 17. Bb6a7 Having gone as far as we can, we'll need to slide rooks along the edge of the board to open up space on the other side. This is where the space on c4 comes in handy. 18. Nb6 19. c4 20. c3 21. Rc2 22. Rd1c1 23. Re1d1 24. Rf1e1 25. Rg1f1 26. Rh1g1 27. Rh2h1 28. Rh3h2 29. Nh3 30. Bg5 31. Bg7h6 32. Bf8g7 33. Be7f8 34. Bd8e7 We're not getting much further on dark squares, so we move our king to the light. 35. d8 36. Kd7 37. c7 38. c6 39. Nc5 40. Be4 41. Be6f5 42. Ke6 43. d7 44. Bd6 45. Bf8e7 46. f8 47. Kf7 48. Be6 49. f5 50. Bg5f4 51. Bh6g5 52. Rh7h6 53. Rh8h7 54. Rg8h8 55. Kg8 One last maneuver tucks the bishop in below the king to open up a path home. 56. f7 57. Bg7f6 58. Rg7 59. Rh8h7 60. Kh8

• Very elegant solution, but I think instead of Rh8g7 you mean Rh8h7 for move 59. Nov 29 '16 at 21:20
• Yes, of course, fixed. Nov 29 '16 at 21:21

56 moves

Clear b6 (4 moves)
Move king to c7 (11 moves)
Free e4 (5 moves)
Free d8 and move king to d7 (6+2 moves)
Free e4,f4,f8 (3+2+4 moves)
Move the king to f6 (8 moves)
Move the king to g7 (6 moves)
Move the king to h8 (5 moves)

All moves using the from-positions:
e4 c5 c4 b6 a7 a6 a5 b6 c7 b8
a8 a7 b6 c7 b8 a7 b6 c4 c3 e4
g5 h6 g7 f8 e7 d8 d7 c7 c6 c5
e4 f5 f4 g5 h6 g7 f8 f7 f6 e7
d7 e6 e7 f6 e6 e5 f4 g5 h6 g7
f6 g5 h6 h7 h8 f7