Introducing Sudoku 7

For fans of Killer Sudoku, Samurai Sudoku and other variants

Introducing Sudoku 7

Postby koushanejad74 » Mon Oct 14, 2019 9:18 pm

Sudoku 7 is a logic-based number-placement puzzle. It is distinct from but shares some properties and rules with Sudoku.
Rules:
• Every column must contain all the digits from 1 to 7
• Every gray cell and its 6 neighbors must contain all the digits from 1 to 7

Here's a sample with it's solution:

Problem:
Sudoku7ProblemIntro.png
Sudoku7ProblemIntro.png (51.44 KiB) Viewed 185 times


Solution:
Sudoku7SolutionIntro.png
Sudoku7SolutionIntro.png (62.89 KiB) Viewed 185 times


And here is an easy one to warm up:
Sudoku7_Sample001_Easy_Problem.png
Sudoku7_Sample001_Easy_Problem.png (51.5 KiB) Viewed 185 times

More challenging samples will be posted soon.
koushanejad74
 
Posts: 75
Joined: 31 July 2019

Re: Introducing Sudoku 7

Postby Mathimagics » Tue Oct 15, 2019 1:30 pm

These do look interesting! It's a neat concept. 8-)

A suggestion - wrap your solution images with [hidden=Solution] tags ...
User avatar
Mathimagics
2017 Supporter
 
Posts: 1480
Joined: 27 May 2015
Location: Canberra

Re: Introducing Sudoku 7

Postby creint » Tue Oct 15, 2019 4:55 pm

Both have a valid single solution:

Solution:
Hidden Text: Show
Code: Select all
  1   6   5 
6 7 2 7 4 6 7
3 4 5 3 2 1 3
2 3 1 4 6 2 4
7 5 6 5 7 3 5
1 6 3 2 1 7 2
4 2 7 1 5 4 6
5   4   3   1


Here are one's which requires locked singles:
Hidden Text: Show
Code: Select all
  .   6   . 
6 7 2 . . 6 .
. . . 3 . . 3
. 3 . 4 . . .
7 . . 5 7 . 5
. 6 . . . . 2
4 . . . . 4 .
5   .   .   .

  1   6   . 
. . . . . 6 .
3 . . 3 2 1 3
2 . . 4 . . 4
. . . 5 . . .
1 6 3 . . . 2
. . 7 . . 4 .
.   .   .   .
creint
 
Posts: 146
Joined: 20 January 2018

Re: Introducing Sudoku 7

Postby tarek » Tue Oct 15, 2019 9:24 pm

That is lovely,

I'm sure you must have looked into the simpler rule "each line of hexagons can't have repeating numbers" which makes it very close to Hanidoku (avoid the consecutive rule). But that in addition to the grey cell and its neighbours having the same rule makes the puzzle very constrained and may not work.

Excellent work with the visuals and the ability to do it in text representation is good too.

tarek
User avatar
tarek
 
Posts: 3352
Joined: 05 January 2006

Re: Introducing Sudoku 7

Postby Mathimagics » Tue Oct 15, 2019 11:03 pm

Nice too from a software solver perspective - if you have a solver that can do arbitrary houses (like fsss2 then it is easily adapted to solve these ...

I see that creint has already got his (very) flexible solver onto it ...

BTW, I don't see a rule in the original post that adjacent cells must have different values, but surely this is a rule?
User avatar
Mathimagics
2017 Supporter
 
Posts: 1480
Joined: 27 May 2015
Location: Canberra

Re: Introducing Sudoku 7

Postby koushanejad74 » Wed Oct 16, 2019 3:57 am

Mathimagics wrote:Nice too from a software solver perspective - if you have a solver that can do arbitrary houses (like fsss2 then it is easily adapted to solve these ...

I see that creint has already got his (very) flexible solver onto it ...

BTW, I don't see a rule in the original post that adjacent cells must have different values, but surely this is a rule?


adjacent cells may have identical numbers as long as other rules are not violated
koushanejad74
 
Posts: 75
Joined: 31 July 2019

Re: Introducing Sudoku 7

Postby koushanejad74 » Wed Oct 16, 2019 3:59 am

Thanks a ton guys for you comments,

I have a version where the diagonals with 7 cells form a group too, what do you think?
koushanejad74
 
Posts: 75
Joined: 31 July 2019

Re: Introducing Sudoku 7

Postby Mathimagics » Wed Oct 16, 2019 7:47 am

Generally speaking, adding additional houses can be good, but only up to a point.

Standard Sudoku is what I call a 3D puzzle, which just means that the cells are partitioned into complete houses (9 cells) in 3 ways (row, cols, boxes).

SudokuX is a 3.2D puzzle, 3 house partitions + 2 extra houses (the diagonals).

I think you can actually find somewhere in this section of the forum where I created a 6D puzzle!

Some general issues that apply are:

  • Rendering: if the additional houses require specific identification (that is, are not intuitively obvious) then both image and printed forms of the puzzle have to be considered.

    For example, SudokuW (aka Windoku), has a simple rendering solution, by using shading on the grid. SudokuP ("Disjoint Groups") can use colours when rendered on a screen, but actually needs no special handling at all, because the 9 "position in box" houses are intuitively obvious to most people. All you need to do really is LABEL the grid as a type SudokuP where this is not already clear.

  • Solution space: each additional house reduces the solution grid space. This can be taken to excess, and make it harder to find valid solution grids from which to create your puzzles

  • Solver experience: additional houses also allow you to produce puzzles that have few clues, and again, this can be taken to extremes. I remember someone (was it tarek?) discovering that 11-clue SudokuP puzzles (the minimum) tend to be much, much harder for P&P solving than a 17-clue vanilla Sudoku

Having said all that, your diagonals idea is most probably a good one!

It has none of these issues, and would probably be just as enjoyable as SudokuX is! 8-)
User avatar
Mathimagics
2017 Supporter
 
Posts: 1480
Joined: 27 May 2015
Location: Canberra

Re: Introducing Sudoku 7

Postby Mathimagics » Wed Oct 16, 2019 7:54 am

koushanejad74 wrote:adjacent cells may have identical numbers as long as other rules are not violated


Ok, that's interesting.

The "no adjacent cells can have same value" rule is almost universal, so I think it would be wise to specify that this restriction does not apply in the list of rules! And perhaps use a puzzle with 2 adjacent clues having the same digit as your demonstration puzzle. You can't go wrong then ...

Is this restriction not applied because of the "solution space reduction" issue?
User avatar
Mathimagics
2017 Supporter
 
Posts: 1480
Joined: 27 May 2015
Location: Canberra

Re: Introducing Sudoku 7

Postby koushanejad74 » Wed Oct 16, 2019 1:19 pm

Here's a sample where diagonal constraint is added,

Sudoku7_Sample002_Easy_Problem.png
Sudoku7_Sample002_Easy_Problem.png (96.26 KiB) Viewed 135 times
koushanejad74
 
Posts: 75
Joined: 31 July 2019

Re: Introducing Sudoku 7

Postby creint » Wed Oct 16, 2019 3:56 pm

Here is an hard one:
Hidden Text: Show
Code: Select all
  .   2   . 
7 . . . . . 2
. . . . . 6 .
. . . . . . 3
. . . . . . .
. . . . . . .
. 5 . . . 4 .
.   .   .   .
creint
 
Posts: 146
Joined: 20 January 2018

Re: Introducing Sudoku 7

Postby tarek » Wed Oct 16, 2019 7:45 pm

The simple rule of "non-repeating (or in other words: different) numbers in a line of hexagons" means 1-7 in a line of 7 hexagons. It can be extended to all lines even the smaller ones with less than 7. a line of 6 hexagons would have six different numbers out of the set 1,2,3,4,5,6,7
User avatar
tarek
 
Posts: 3352
Joined: 05 January 2006

Re: Introducing Sudoku 7

Postby Mathimagics » Thu Oct 17, 2019 1:53 am

Good idea, tarek!

It would further reduce the set of solution grids, of course ...
User avatar
Mathimagics
2017 Supporter
 
Posts: 1480
Joined: 27 May 2015
Location: Canberra

Re: Introducing Sudoku 7

Postby koushanejad74 » Thu Oct 17, 2019 3:20 am

Tarek,

Actually that was my initial design, I'll post one like that soon,

Thanks,

-Kousha
koushanejad74
 
Posts: 75
Joined: 31 July 2019

Re: Introducing Sudoku 7

Postby Mathimagics » Thu Oct 17, 2019 4:00 am

Kousha,

I'd prefer it you don't draw lines through the diagonals! 8-)

You can simply indicate by rules, eg "All full-length diagonals have different digits", or "All diagonals have different digits" for Tarek's suggstion.

While I think of it, did you actually try the standard puzzle with the adjacent-cells-differ rule, and then found that it was hard (or impossible) to get solution grids?
User avatar
Mathimagics
2017 Supporter
 
Posts: 1480
Joined: 27 May 2015
Location: Canberra

Next

Return to Sudoku variants

cron