There are very nice Sudoku variations which are inspired from Kropki Sudoku Puzzle. In last years' Grand Prix Sudoku Championship by World Puzzle Federation there was Thropki Sudoku. This years' Sudoku GP, which is on coming weekend, we have Double Kropki Sudoku Puzzle. Difference of Double Kropki Sudoku puzzle from Kropki Sudoku is that in Double Kropki when the difference between two adjacent cells is 2 and ratio is 4 then symbol markings are used.  From instruction point of view, this does not look much of difference but solving approach for 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 practice of 4th Round of Sudoku GP 2018 and I am publishing it as part of Fun With Sudoku Series as 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)
Answer of this Double Kropki Sudoku puzzle can be viewed by clicking on button. Please do give your best try to solve this Sudoku puzzle before looking at the answer.

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

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 :)