Hardest Sudoku I've ever seen

[Nicholasp27]

so far i haven't done any guessing; i'll let u know if i had to when finished

[kokiri]

doesn't colouring imply guessing?

i mean that i would only use a colour change if i'm stuck, but have a cell that is either 5 or 9. Then i try 5 in another colour until i hit a contradiction and, if so, switch back to 9. I view that as guessing.

Playing around with this one, it occurred to me that this sort of guessing/scenario testing, is probably much quicker than my usual technique. Usually I go in a cycle that runs:

1) do all the obvious deductions
2) do some less obvious ones
3) get stuck and hunt around for a new complicated deduction.

Where step 3) is way the slowest. By replacing 3) with 'choose a 50% shot and see if it leads to a contradiction', as long as you have an audit trail, the slowest part of the techniques is removed, at the expense of potentially being wrong.

i hate these things with a passion.

[bojtun]

Yep, I got in a spot fairly early where column 5 was down to two spots and I felt like I was kind of stuck everywhere else with 2/3/4 possibilities in lots of places ... tried one of the numbers in column 5, ran into a road block ... then plugged in the other one and cruised along at a decent pace.

I prefer "trial and error" over "guessing" ... [img]/images/graemlins/tongue.gif[/img]

[Stephen H]

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doesn't colouring imply guessing?

[/ QUOTE ]

That's a long discussion but I can see the complaint. I turned off coloring as an option and it solved it just using Xwing and Ywing deductions on top of the basic stuff.

Having to do multiple Xwings to solve a Sudoku is pretty obnoxious and easy to miss so I would definately classify this as a darn hard Sudoku.

[durron597]

i've been going to guessing before y wing... mostly because i didn't know y-wing prior to this thread

thats probably why i thought this one was so hard

[RoundTower]

I had to guess at one spot, after I was only sure of 14 more numbers. But the guess disproved itself fairly quickly. It took me a bit more than half an hour, but I haven't done very much sudoku and I have no clue what all these techniques you mention are.

[RoundTower]

also, I solved mine in MSPaint. Standard, or is there a tool to use that isn't cheating?

[mute]

Finally got this done. No guessing, but took me a couple of hours. I'm really out of practice with these.

Used a bunch of x-wings and one forced chain.

I hadn't heard of y-wings either. Gonna be looking for those in the future.

[Neil S]

I'd never heard of any of this stuff. No wonder I was toast in gamesapalooza, heh.

[kristiefix]

Ah, Sudoku... it doesn't look too bad, I'll take a crack at it.

[img]/images/graemlins/heart.gif[/img]