There are very nice Sudoku variations that are inspired by Kropki Sudoku Puzzle. In last year's Grand Prix Sudoku Championship by World Puzzle Federation, there was Thropki Sudoku. For this year's Sudoku GP, which is on the coming weekend, we have the Double Kropki Sudoku Puzzle. The difference between the Double Kropki Sudoku puzzle from Kropki Sudoku is that in Double Kropki when the difference between two adjacent cells is 2 and the ratio is 4 then symbol markings are used.  From an instruction point of view, this does not look much difference but the solving approach for the Double Kropki Sudoku puzzle is entirely different from Kropki Sudoku. In Double Kropki we need to mark even and odd cells to proceed in Sudoku solving which is not required while solving most of the Kropki Sudoku puzzles. Anyway, today's Double Kropki Sudoku puzzle is for the practice of the 4th Round of Sudoku GP 2018 and I am publishing it as part of the Fun With Sudoku Series as the 309th Sudoku Puzzle in this Series.

## Rules of Double Kropki Sudoku Puzzle

Standard Sudoku Rules apply. Additionally, Adjacent cells containing numbers whose difference is 2 are marked with a white symbol. Adjacent cells containing numbers whose ratio is 4 are marked with a black symbol. Adjacent cells with no marking must not contain numbers either whose difference is 2 or whose ratio is 4.
 Double Kropki Sudoku (Fun With Sudoku #309)
The answer to this Double Kropki Sudoku puzzle can be viewed by clicking on the button. Please try your best to solve this Sudoku puzzle before looking at the answer.

This Double Kropki Sudoku Puzzle I am publishing as the #309th Sudoku puzzle in the Fun With Sudoku Series. Here are the next and previous Sudoku puzzles published in this series.
The previous Sudoku Puzzle is Arrow Sudoku Puzzle (Fun With Sudoku #308)

kishy said...

9:23.Little bit of a sticky solve but learnt a thing or 2 in this variant.

Rajesh Kumar said...

I learned after solving this Double Kropki Sudoku is that we need Even Odd Markings to solve this Sudoku type.

Rakesh said...

9.20 - The white circle solve was similar to consecutive N sudoku. I also learnt some tricks, the main one being that 3 evens are used by two nonconsecutive black circles in a row/column/box, so any white circles there will have odd numbers only.

Gaurav Kumar Jain said...

Nice and teaches a completely different variant...15 mins

Aashay Patil said...

16:09, tricky solve!

Rajesh Kumar said...

Yes, This was tricky and I am hoping that this will be good practice for Sudoku GP :)