Tuesday, 12 June 2012

Puzzle #113: Easy as Japanese Sums

I encountered this puzzle type the first time when test solving Serkan Yurekli's puzzle set for last year's 24 hour puzzle championship. I really liked them, although they caused more trouble than you'd expect for their size. Even though the puzzle idea is very similar to Japanese Sums puzzles, the Latin Square component in this genre makes solving a lot different though. Only later I found that the genre also existed on Naoki Inaba's website.
This is the first time I tried to create one myself. I like how it turned out. It's moderately difficult.

Rules for Easy as Japanese Sums

This puzzle uses the digits 1-5.


  1. I solved it and enjoyed it.
    I get the impression, though, that you wanted to include a 12 and a 15. Am I right?

    1. Well I was aiming for all different clues actually as I had no idea how many clues I'd need. I could have done it by putting a 15 in C7 instead of a 9 in C6, except that broke up part of the logic.
      After looking it over I saw there is an option to create a 1~14 puzzle, by removing the 9 in C6, moving the 2 to C7 and putting a 12 above C7. Except that puzzle is a lot harder than this one, although it's logically solvable.
      In the end, this is the best result in my opinion.

  2. Brilliant and excellent puzzle! Like cyrebjr I also enjoyed it much!

    Will try your 1~14 version, or would you consider making an image for it?

    Suggestion: it would be better if you could include the information "digits 1-5 used" within the image, as it is not immediately obvious from the image as of now.

    1. I guess I could do that. I just thought it looked cleaner with the information added outside the image.

      Here's the image of the alternative.


    2. Thank you so much. Will try the alternative soon!

  3. Phew... Finally grind out the 1~14 alternative. It is indeed much tougher than the original. Too bad you couldn't squeeze in a 15 to make it 1~15!

    Here is the solution as a single line:


    (Sorry don't know a good way to hide the spoiler while allowing easy retrieval. Any suggestion?)