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After this puzzle has been solved, it is time to offer our clever solvers another Loser Chess game to reconstruct...

Do you remember that I often pay a visit to my friends Fabi and Mag on evenings ? Most often I find them bending over a chessboard. They love to play chess, but once in a while, they experiment with Loser Chess instead of the more mundane game. It was the case last night, and when I arrived Mag, sitting in front of the white pieces, was thinking in this position:

Usually Loser Chess involves lots of early captures, but here only one bishop was missing, so I was surprised when Fabi told me that he had already played his 18th move !

Can you help me understand how they reached that position ?

In Loser chess, the rules are the same as in classical chess but for the following points:

• The king behaves just as any normal piece and can be captured. There is no check, no checkmate, and the king being under attack is not an issue if you want to castle.




• If you can capture a piece, you have to capture it.




• If you can capture several pieces, you can choose to take whichever of them.




• In case of a promotion, a pawn can be changed into a second king.




• You win if and only if you are stalemated, i.e. either when your opponent has taken all your pieces or when none of your remaining pieces can move.

(as a consequence, Mag's next move is forced: he will play 19.Bxh6, and Fabi will have to choose between 19...Rxh6 and 19...Nxh6)

This problem was created by Michel Caillaud in 2006.

Hint 1

The first (easy) step is to find out on which square the single capture has happened.

Hint 2

When this problem was first published, it came with the header "Le refuge secret", which translates to "the secret hiding place".

I think white has to clear the d2 square for the black bishop somehow. We can get there in 19 moves...


1. d3 Na6

2. Kd2 g5

3. Ke3 g4

4. Ke4 Nb8

5. Ke5 Na6

6. Bf4 Nb8

7. Bg3 Na6

8. Na3 Bh6

9. Qb1 Bd2

10. Qd1 Bb4

11. Nb1 Ba3

12. bxa3 Nb8

13. Bf4 Na6

14. Bc1 Nb8

15. Kd4 Nc6

16. Kc3 d5

17. Kb3 Be6

18. a4 Qd7

19. c3 h6

I think this is it: https://lichess.org/ftOCzIHy

1. d3 Nf6 2. Kd2 g5 3. Ke3 Bh6 4. Bd2 Rf8 5. Bc3 Ng8 6. Bh8 g4+ 7. Kd4 Bg5 8. Na3 h6 9. Qb1 Bd2 10. Qd1 Bb4 11. Nb1 Ba3 12. bxa3 Nc6+ 13. Kc3 d5 14. Kb3 Be6 15. Bb2 Qd7 16. Bc1 Nf6 17. c3 Rh8 18. a4 Ng8

Well here goes another week!

First step, finding out the capture:

bxa3, which means Ba3 had to happen.

Absolutely required moves for white (4): bxa3, a4, c3, d3

Absolutely required moves for black (2): Ba3, h6

Time to clean out the black squares for the bishop!

Moves for white to setup black bishop moving (9):

d3, Kd2, [Kc3 | Ke3], [Kd4 | Ke4], Ke5, Bf4, Bg3, Na3, Qb1


Moves for white to reach ending position (10):

bxa3, Qd1, Nb1, Bf4, Bc1, a3, c3, King 3 moves

EDIT: I can't cut that down any more and it's at 19. I think the king moves too much. There also isn't a secret hiding place.

EDIT: I found the secret hiding place!

The white bishop hides in h8!