... by: jos jansen, netherlands
Something is not clear with respect to the rules for black fields. These cannot be filled with numbers, but I supposed that their their possible content should obey the strict rule that each number can only appear once in each row and column. In the solution of e.g. puzzle #48 of January 4th this rule is clearly violated: in the solution the content of square G8 becomes 1, whereas the black square D8 should carry 1 according to the strict rule. So under the strict rule the puzzle has no solution. Therefore a relaxed rule should explicitly be added with respect to the black squares, which will make the puzzles less attractive (in my opinion!).Kind regards,
Jos Jansen
Jeff Widderich writes (4-Jan-2009):
Hi Jos Thanks for getting in touch. Allow me to re-quote your quote of the rules on black cells - "strict rule that each number CAN only appear once in each row and column" - This does not imply ALL numbers MUST appear - merely that those numbers which do appear can't repeat in rows and columns. The rule is sudoku-esque but its not exactly the same. It’s a constraint but we don’t expect you to find nor require values in black cells (unless we're given a clue) since most black cells could have more than one number (including those with clues). Hopefully you'll find the puzzle a little easier now you don’t have to worry about 'hidden black cell values'.
On a side note, we've really sweated on the rules because of space conciderations in newspapers and so on, so if you have a better wording we'd be very pleased to read it.
Best wishes for the new year