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CiSRA Puzzle Competition 2010 - Solutions

4B. Chebble

Chebble is a portmanteau of Chess and Scrabble. The first step is to drop the chess pieces straight down onto the board of letter tiles.

4B. solution 1

Some of the tiles are raised. The raised tiles are all of the squares to which one or more of the chess pieces could legally move under the normal rules of chess (avoiding check for the kings and so on). This suggests that the next step might involve looking at where each of the pieces may move. Black is conventionally at the top, so the pawn moves down the board.

It turns out that, for each piece, the total Scrabble point value of the tiles that it could legally move to is a number within the range 1 to 26, which conveniently maps to the alphabet.

The squares that each of the pieces can legally move to are shown below. They're ordered by one piece of information we haven't used so far: the height of the pieces in the puzzle. Where two pieces are at the same height, they're ordered by depth. In other words, they're ordered left-to-right then top-to-bottom from the viewpoint used in Blockhead.

4B. solution 2

The total point values of the tiles to which each piece can move are:

  • White knight: 22
  • Black pawn: 5
  • White king: 18
  • White rook (left): 12
  • Black king: 9
  • White rook (right): 14
  • White bishop: 19
  • Black bishop: 11
  • White queen: 25

Converting these numbers to letters of the alphabet spells out the surname of chess master Boris Markovich VERLINSKY.

Puzzle design notes: The letters that the chess pieces land on can be arranged to spell what looks like a message: "ordered by". This was neither a deliberate clue, nor a deliberate red herring. It is, in fact, a complete coincidence, and something that we didn't even notice until some teams started guessing it as a possible solution. During test solving, the chess pieces were in slightly different positions, and they landed on letters that anagrammed to give the word boergeder, which is apparently Danish for a popular breed of domestic goat. This led us down many wrong alleys, as we guessed a slew of goat-related and Danish words. So we tweaked the puzzle to avoid this problem. Unfortunately we didn't check carefully enough what letters the chess pieces landed on after the tweak.