## Sum-Sudoku 7

For fans of Killer Sudoku, Samurai Sudoku and other variants

### Sum-Sudoku 7

Sum-Sudoku 7 is a logic-based number-placement puzzle. It is distinct from but shares some properties and rules with Sudoku.
Rules:

• Every gray cell and its 6 neighbors must contain all the digits from 1 to 7
• There are black dots, three cells adjacent to each dot must have numbers such that the biggest number is equal to the summation of the other two

Sudoku7_Sum_001_Problem.png (52.69 KiB) Viewed 344 times

Posts: 77
Joined: 31 July 2019

### Re: Sum-Sudoku 7

Clearly the vertical non-repeat rule does not apply.

Are all the black dots given? I.e. if a corner has no dot can we assume it does not sum? From my current partial solution - NO.
HATMAN

Posts: 272
Joined: 25 February 2006
Location: Nigeria

### Re: Sum-Sudoku 7

vertical non-repeat rule does not apply
If a dot is present, then the cells must add up; but if the cells add up there may or may not be a dot

Posts: 77
Joined: 31 July 2019

### Re: Sum-Sudoku 7

Single solution within 0.3 seconds using a solver:
Hidden Text: Show
5 2 5
4 2 1 1 4 7 6
7 6 3 5 2 3 1
5 1 4 7 6 4 5
2 7 3 6 1 2 7
6 3 4 2 5 7 1
2 5 1 1 3 4 6
creint

Posts: 230
Joined: 20 January 2018

### Re: Sum-Sudoku 7

creint wrote:Single solution within 0.3 seconds using a solver:
Hidden Text: Show
5 2 5
4 2 1 1 4 7 6
7 6 3 5 2 3 1
5 1 4 7 6 4 5
2 7 3 6 1 2 7
6 3 4 2 5 7 1
2 5 1 1 3 4 6

Could you please let me know what solver you used?

Posts: 77
Joined: 31 July 2019

### Re: Sum-Sudoku 7

Using "The Z3 Theorem Prover" and applying the necessary constraints, partly automated with my solver.
creint

Posts: 230
Joined: 20 January 2018

### Re: Sum-Sudoku 7

creint wrote:Using "The Z3 Theorem Prover" and applying the necessary constraints, partly automated with my solver.

How do I get this solver?

Posts: 77
Joined: 31 July 2019

### Re: Sum-Sudoku 7

Pasting the term in a search engine gives:
https://github.com/Z3Prover/z3

My solver is not very user-friendly and not very public.
Without the custom code it won't solve this puzzle.
But if you really want to test it and you think that less user-friendly is still usable, you can get my solver.
creint

Posts: 230
Joined: 20 January 2018

### Re: Sum-Sudoku 7

creint wrote:Pasting the term in a search engine gives:
https://github.com/Z3Prover/z3

My solver is not very user-friendly and not very public.
Without the custom code it won't solve this puzzle.
But if you really want to test it and you think that less user-friendly is still usable, you can get my solver.

Thanks man

Posts: 77
Joined: 31 July 2019

### Re: Sum-Sudoku 7

Can I check: is this one meant to be human solvable?

If so I have four different partial solutions with lots of pencil marks as well that are not obviously narrowing down. Am I missing some technique?
HATMAN

Posts: 272
Joined: 25 February 2006
Location: Nigeria

### Re: Sum-Sudoku 7

HATMAN wrote:Can I check: is this one meant to be human solvable?

If so I have four different partial solutions with lots of pencil marks as well that are not obviously narrowing down. Am I missing some technique?

I'll post a solver soon,