The New Sudoku Players' Forum

[primeprover]

I was fiddling around with JSudoku and ended up finding this variant. Unfortunately, I am having no luck in solving it at all. Is anyone skilled enough to solve this puzzle without branching? Could you show what I have missed?

Puzzle rules:

1. Normal sudoku rules apply
2. Anti-knight - no number can be a knights move away from itself.
3. Ferz-non-consecutive - no consecutive numbers can be diagonally adjacent.

Code: Select all

..9|...|7..
...|...|...
7..|...|..9
---+---+---
...|.8.|...
...|6.2|...
...|.4.|...
---+---+---
3..|...|..4
...|...|...
..5|...|8..

As a side note: Is 12 clues the minimum number of clues for this variant?

[tarek]

I will be able to give you a comprehensive answer in 48h

Watch this space!

Tarek

[creint]

JSudoku won't give me a solution, it said multiple solutions.

But my solver gave single solution:

Hidden Text: Show

Code: Select all

2 8 9 1 3 4 7 6 5
1 5 4 9 6 7 2 3 8
7 6 3 2 5 8 1 4 9
9 7 6 3 8 1 4 5 2
5 4 1 6 7 2 9 8 3
8 3 2 5 4 9 6 7 1
3 2 7 8 9 6 5 1 4
4 9 8 7 1 5 3 2 6
6 1 5 4 2 3 8 9 7

Required 4 levels of chains/nets. Hard but not that hard. Rating should be around SE 9.0 or lower.

[tarek]

I was fiddling around with JSudoku and ended up finding this variant. Unfortunately, I am having no luck in solving it at all. Is anyone skilled enough to solve this puzzle without branching? Could you show what I have missed?

This is an extremely tough puzzle. I modified Sukaku Explainer to support Ferz NC and with the set of techniques available it couldn't solve it (the solver still needs some tweaking but overall I think still a difficult puzzle). I confirm the unique solution that creint has also mentioned.

Solvable is the following:

Code: Select all

.........
...5.....
.....65..
.9....1..
.........
..5....9.
..12.....
.....1...
.........


As a side note: Is 12 clues the minimum number of clues for this variant?

No.

Code: Select all

.........
.........
.........
......3..
.........
..6......
...9.....
.......7.
.........


[primeprover]

Thanks for having a look. It looks like this puzzle is hard enough that an extreme amount of effort is needed to find a solution. This is beyond a lot of solvers(without recursion) including humans.

JSudoku gave me the unique solution after recursively solving.

[tarek]

I generated a few & rated them with an un-released version of sukaku explainer:
Here is one that is solvable & SE rates it at ER=3.2 (X-Wing)

Code: Select all

...3.....
.....9...
.....6...
4.....67.
.........
.58.....1
...6.....
...9.....
.....7...


[HATMAN]

Nice puzzle

Early on I used a couple of FNC/AN interactions that I thought neat and hoped to avoid the x-wing, but as I plodded on there it was.

I remember making quite a few of these early on (probably as killers) as I found NC/AN too restrained.

[tarek]

Nice puzzle

Early on I used a couple of FNC/AN interactions that I thought neat and hoped to avoid the x-wing, but as I plodded on there it was.

I remember making quite a few of these early on (probably as killers) as I found NC/AN too restrained.

thanks for the feedback, I'll post a few of these on the forbidden pairs thread in case there is an interest

tarek

[tarek]

Another fun to solve puzzle
This is an AN FNC+ (Ferz Non consecutive including 1,9 and Anti-kNight)

Code: Select all

.........
...9.5...
.........
.5.....1.
.........
.2.....5.
.........
...2.7...
.........


[tarek]

Sukaku Explainer v1.17.7 has been released

It would solve/rate/analyze puzzles with Ferz non consecutive and Ferz non-consecutive +

Here is the analysis for the above FNC+ puzzle

Code: Select all

Analysis results

Difficulty rating: 3.6 (Generalized Naked Triplet)

This Anti-kNight Ferz NC+ Sudoku can be solved using the following logical methods:
64 x Hidden Single
1 x Direct Hidden Pair
8 x Naked Single
1 x Non-Consecutive Forcing Cell
16 x Locked Non Consecutive
13 x Generalized Intersections
1 x Generalized Naked Triplet

The most difficult technique (ER): Generalized Naked Triplet

solution: Show

Code: Select all

432871965
871965432
965432871
654328719
719654328
328719654
287196543
543287196
196543287


Tarek

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