Shatranj problem, June 2015

Saturday, 6th June 2015

Here's the solution to April's problem. Note that the colours are reversed, and white's pawn is travelling down the board. 1. Rook g1-g8 (check), king c8-b7; 2. rook g8xa8, king b7xa8; 3. king d6-c7, knight d3-f4; 4. pawn h3-h2, knight f4-d5 (check); 5. king c7-c8. White, according to Murray, can easily prevent the black king from moving. Note that due to the confusion of white moving down the board, I originally had the board drawn with notation reversed; this has now been corrected on April's blog post.

A Reminder of the Rules of Shatranj

This is a brief reminder, for chess players, about how shatranj, or mediaeval chess, differs from the modern game.

The king, rook and knight move as the modern pieces do. The pawn only ever moves one step forward, never two. The bishop moves exactly two squares diagonally, and can jump over a piece in the way. The queen moves diagonally to an adjacent square, much like a draughts king.

Castling and en-passant moves are unknown. A pawn always promotes to a queen. Stalemate is a loss for the trapped player, and if one side is reduced to only a king then that player has lost the game.

The diagram shows the full setup of the pieces, and illustrates the symbols used for each of the pieces in the mediaeval game. For a full discussion of the game, including a full set of rules, see the Shatranj page.

This month's puzzle also has white moving down the board: I'll not get confused this time. The solution to this one is simple and comes from a game by Yusuf at-Turki, a shatranj player about whom I can find no further information. Black is to play next and wins the game. Can you spot how?