dp_94 - 2016-03-23 7:11 PM

you made a mistake at R9C4 possible candidates should be 579 and 6 can not be there since 6 is already in that box but this sudoku also requires some advanced sudoku techniques like colouring, XYZ Wing,X-Y Chain. In Completion Even the world best sudoku solver's guess in such kind of puzzles they just wait a few seconds if they dont get any clue they just guess at that point some even guess multiple times.


you can try this site for better understanding of these kind of advanced techniques http://www.sudokuwiki.org/sudoku.htm

and these for practice

http://www.mindoku.com/games
http://www.sudokucup.com/
http://www.fed-sudoku.eu/enindex.php?co=vysl&tab=easy
http://www.speedsudoku.com/public.php?mode=home&no_cookies=