The sudoku app which generated this puzzle also can give a hint, but I'm afraid that it would just spit out the correct answer without a proper explanation.
What I need to know is what technique I should study to see some pattern in this one?
I learnt about X wing, I learnt about Y wing, I think I know the most common techniques (naked single, matching pair... etc.), but I cannot see any pattern here.
Do I miss something fundamental which I should know already but I simply missed it, or if I should study for some particular technique, could you just tell me which one?
At the same time, the Sudoku app things I haven't made a mistake yet in the cells I already filled. (not talking about the candidates though) ... so, in the least I should be able to exclude a mistake on my part.
