For the easy and medium ones, I find a good way to start (and finish quickly) is to find yellow squares of the same number in the same row of 3x3 blocks. Then I go and find the third one and make a decision of whether I can narrow it down to one spot, and then place the number in that cube, then try to go perpendicular to the first direction. After doing this with each number 1-9, you might get some more information and can do another pass, so if you're lucky you'll have, say, a 5 in every 3x3 grid to start with.

Otherwise, for the harder ones, I'll go through the entire grid, and if I can narrow it down to three or fewer numbers I will type that into the square. If I can't narrow it down the three numbers, I put an X in the square, meaning I have already visited it once.

Once I have get it down to one number, I put a * by it.

That tells me I may have enough information to turn some of the "X" squares into numbers by narrowing down the values possible. Of course at this point you should also remove that number anywhere else in the row, column, or 3x3. Which is what I often forget to do and why I have to restart the puzzle again! :)

The other thing is to try to get the grid down to n squares with n values, for example, 145 in three squares, then you know the other six squares are guaranteed to be 236789.

After all that fails, I write down the grid, at a point I know(believe) to be valid, and make a guess and then see if it works or if I have to restart.

But you might use other symbols in the grid, say to indicate that a number must be in one of two spots, which I don't do because I don't have space to do both techniques.

wow, that's a interesting way of doing it!

I go for the obvious first, do a quick scan and find the ones that can only go in one place

Then i start to go by rows and columns, picking the ones that have the most amount of numbers, you can usually find missing numbers by looking at a certain row and checking for your missing number by looking at the column across from it and seeing whether that number is already there.

If I run outta options by doing that, I again target rows and columns and sometimes the blocks too, but ones that are missing 3-4 numbers, sometimes you can determine a number this way. First select a column missing 3 numbers, say your looking for a 3,5,9, by scanning the adjadcent rows you see one with a 3 and a 9 in the same one...you therefore know that only the 5 can go there, that's usually how i find the "key" numbers that will unlock the whole board for me.

Usually rinse and repeat this process till my eyes bleed and my brain hurts, then I start guessing. Find the one row, column, block where one number can go in only 2 places, mark it with a 0 and go from there, marking all my numbers from that point with a 0 for easy backtracking. If it doesn't work, erase the 0'd ones, replace that one number and start again (subtracting the 0's since i know it's right)


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~I'm not addicted! I'm just proofreading!~

ty for the tips

Velcromagnon

In one of your post you wrote:

"After all that fails, I write down the grid, at a point I know(believe) to be valid, and make a guess and then see if it works or if I have to restart. "

There is no need to write them done. Take a screen shot and paste it into word or wordpad. You can then save it or print it out.

When in the puzzle hold down the Alt key and hit the Print Screen key. Open word, wordpad, or paint. Click on Edit and Paste. From there save it or print it out.

Hope you can use this tip.

Here's my biggest trick, but its hard to explain.

You look at each group of nine. you find a block where a column and row intersects that have two numbers that are the same but not in your target block.

for instance say in a column you have a 3 and a 2 then in a row you have a 3 and 2 . The column and the row intersect, but the 3 and the 2 are not in the block of the intersection - the trick is look for this type of intersection where the result will be that the two numbers result in an either/or choice, then even though you don't which is which, you can still count those blocks as 'filled' with the 3 and the 2-- and that will probably help you figure out 1 or more of the the other squares in that block.

-- nb

I never "guess". And I rarely use the either/or numbers in the same box... It confuses me later. I did like the 'X' tip to keep from going back and looking at the same combination again, I may try that. Perhaps it's my inexperience that I've never tried the guess technique.

As for the tips/tricks: when I get overwhelmned on a real nasty one. I use the box to determine what numbers are left. Usually you can confine a couple of them to a given row/column. I then trace that back to see if that eliminates options in the rest of said row/column. Ussually you have to trace that info with a couple of options to another row/column. I keep it all in my head and then back track the logic to make sure it's right.


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Some call me the gangster of love.