dailysudoku.com

[gamonitti]

I seem to be able to do most of the hard and very hard puzzles, but I am curious about two things.
1. Am I employing all possible strategies.
2. What classifies a puzzle as a certain level (criteria used).
3. How are these wonderful puzzles created (I know none can answer).

My stategies enlist organizing the or staements as 1246 for example in a box means either 1 2 4 or 6 can exist in that box.
Then I go through a series of reductions based on:
1. see if there is only 1 number possible in either a row, column, or box.
2. box1 123 box2 23 box3 12 means that the 1, 2, and 3 must be used in the mentioned 3 boxes therefore any box in common row, column, or 3x3 box must have those 3 numbers removed from or statement.
3. My most recently developed strategy employs a limiting choice to a common 3x3 and column or row. If I know that a 2 must exist in the 1st row of a 3x3 box then all other 2's are eliminated from the same corresponding row or column. This strategy seems to be the one strategy that frees up the reduction process for hard and very hard puzzles.
If someone could share another type of srategy with me I would be grateful, however I am self taught in all my methods so far.
P.S. These are great logical reasoning examples which I use in the classroom on the secondary level. I also incorporate these into my afterschool program where I work with some honor students in mathematics. How dare someone say there is no Math involved, as logical reasoning is an important concept in proofs.

[someone_somewhere]

Hi,

So, did you not find a Sudoku that you could not solve with your strategy?

If no, I can help you.
If yes, you have still on what to work.

see u,