King has placed a bounty on Valiant Knight and enlisted his evil queen’s help.

Queen knows knight’s regular stops of his journey and knows he goes through all odd prime cells.

She strategically placed her self in D3 to cover all those cells. Normal chess movements apply for both the Knight and queen.

Based on the info given below, advise the Knight what cells he has to avoid so that he can journey safely.

enter image description here

  • $\begingroup$ what is an odd prime cell? $\endgroup$
    – SteveV
    Jun 29, 2019 at 21:48
  • $\begingroup$ 1,3,5,7,9,11..are all odd..only 3,5,7,11 are odd primes..since there are 64 cells..you have to consider upto 63.. $\endgroup$
    – Uvc
    Jun 29, 2019 at 21:54
  • $\begingroup$ So... the odd prime numbered cells are all in cells that are attacked by the queen? $\endgroup$
    – user46002
    Jun 30, 2019 at 5:49
  • $\begingroup$ Yes..that is the beauty of math-chess connection...to solve this puzzle, knights moves need to be traced back or forward to get the odd prime numbers directly in line of sight of the queen $\endgroup$
    – Uvc
    Jun 30, 2019 at 9:22
  • $\begingroup$ If you put down other intermediate cells also, Picture will slowly get clearer..kind of chess-sudoku $\endgroup$
    – Uvc
    Jun 30, 2019 at 9:44

1 Answer 1


Initial observations:

Odd primes include:

17 squares in total (3,5,7,11,13, 17,19,23,29,31, 37,41,43,47,53, 59,61)

Queen covers:

26 squares


9 squares Q covers are not odd primes, one of them is 6 in A3 (given)

My progress so far:

enter image description here

  • $\begingroup$ You can narrow down your choices much further with given clues..lot of restricted choices to nail down the numbers $\endgroup$
    – Uvc
    Jun 30, 2019 at 9:29
  • $\begingroup$ Just an observation rot13(Gur bqq ahzoref nyy unir gb or ba gur fnzr pbybe fdhner, fb lbh pna ryvzvangr fbzr bs gur ebj/pbyhza cbffvovyvgvrf) $\endgroup$
    – SteveV
    Jun 30, 2019 at 19:36
  • $\begingroup$ Left side..will be lot more productive $\endgroup$
    – Uvc
    Jun 30, 2019 at 22:04
  • $\begingroup$ @OmegaKrypton oh sorry, didn't see that. I was mainly referring to rot13(lbhe frpbaq pbzzrag gung gur dhrra pbiref 26 fdhnerf, ohg gurer ner bayl 18 cbffvoyr fdhnerf sbe gur 17 bqq cevzrf.) which i'm now sure you already knew $\endgroup$
    – SteveV
    Jul 1, 2019 at 2:52
  • $\begingroup$ thanks @Uvc is this better? $\endgroup$ Jul 1, 2019 at 3:12

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