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Another very sparse Sudoku (Posted on 2022-09-02) Difficulty: 5 of 5
In this Sudoku, with normal rules applying, but no starting numbers are given. There are 14 diagonals indicated, each having a sum indicated by a "?". The 14 question mark values add to 178.

The figure is here:

            ?
?  __ __ __/__ __ __ __ __ __
 \|__|__|__|__|__|__|__|__|__| 
  |__|__|__|__|__|__|__|__|__|\
? |__|__|__|__|__|__|__|__|__|\?
 \|__|__|__|__|__|__|__|__|__| ?
  |__|__|__|__|__|__|__|__|__|\
? |__|__|__|__|__|__|__|__|__| ? 
 \|__|__|__|__|__|__|__|__|__|\
  |__|__|__|__|__|__|__|__|__| ?
  |__|__|__|__|__|__|__|__|__| 
  /              /  /  /  / 
 ?              ?  ?  ?  ? 

To guard against any notational confusion, you may confirm that the number of cells in each diagonal, going around CW the top, is: (3, 1, 2, 4, 6, 1, 2, 3, 4, 8, 9, 2, 5, 8). Also, note that some cells are present in two diagonals and so contribute twice to the grand sum of 178.

The puzzle is from the site: "Cracking the Cryptic"

See The Solution Submitted by Steven Lord    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts Solved, but not sharing. Expanded hint. | Comment 3 of 4 |
I looked at the encouragements and decided the 3rd hint might really help.  I don't usually care for Sudoku compared to many other logic puzzles, but I figured I had time so why not give it a go?  Once I got it drawn (I don't have printer with me) with the diagonals lightly shaded I realized how to apply the hint:

In each 3x3 section the squares are either blank or have /, \ or X in them.  You can figure out the smallest possible value by setting the smallest values available in any X and the next smallest in any / or \.

In this way, the nine 3x3 have minimum values:
15, 10, 34
6, 22, 13
23, 15, 39
the sum is exactly 178.  

You can then quickly start finding a lot of the 1's and 2's as well as the 9 in the bottom right 3x3.

I didn't time myself but it probably took about 25 minutes once I finished drawing and calculating.

  Posted by Jer on 2022-09-03 12:53:45
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