+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    | WK |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+
|    |    |    |    |    |    |    |    |
+----+----+----+----+----+----+----+----+

Place 2 queens, 2 white bishops and 2 black bishops on this chessboard so that every square is under attack.

One white king has already been placed (as shown in the above diagram.)

(In reply to re(2): Why the 'white' king? by broll)

That subject was more to provoke thought for what I then thought to be a second consideration for the problem as I "had solved" the first part (which I realised later I hadn't).

True, for the that king's position to be threatened  one would require a black piece, and therefore we'd need a snowballing effect for the other pieces if all squares were to be under threat.

Posted by brianjn on 2013-05-11 20:50:30