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Tough Sudoku for 14/December/2005


Choose a number, and place it in the grid above.

  1 2 3 4 5 6 7 8 9
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Submitted by: Gath

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19:49 Starting to get the hang of this.
Happy sudoku-ing everyone! I'll try it later!
I'm #3!!!!
hi doctor who..

i think i managed this by reversing the polarity of the wolf nortuen.
10:52 with some help. Lovely photo of the dolphins. Who is the good photographer and where were was it taken?
Good night, everyone.
5:26 not too bad
many distractions , but it is done
nice job if you can get it
what do you put on your resume?
would anyone care to share some logics in solving some of these tough puzzles?
im not to good at these 18:00 (im a beginner)
dt, go 'proofs' page, link topright
fifteen mts.
Start with 27 filled.
c1=1 c5=8 c9=5 g1=2 g5=1 g7=6 g8=5 g9=3
pair 49 in Bh8 leads to d7=5
pair 23, 89 in Bb2
pair 12 in Col.e
Remove 3 in Row8
7 or 4 in e4 leads to e2=8
easy to 46 filled
pair 46 in Be5
pair 89 in Col A
Whatever you choose e7=1 or 2 leads to i9=8
Then easy to the end.
well, itis not an easy one.
New to this. Didn't time.
hi, I'm back, after a hiatus due to computer malfunction... missed my daily sudoku fix! Didn't time myself - this one did seem tough to me, took me at least 25 mins. Oh well :))
Ive seen this picture before!!!
Welcome back
18:12 with no guessing! I sent another picture of Ashley Violet in .. but actually I'm still waiting to see a picture of one of the dogs. Moving to archives. See you all later.
really difficult
Full Solution, Part 1 (not checked for typos):

1. Simple elimination: g1=2 (in column-h, 2 must be in either h4 or h6); c9=5 (in column a, 5 must be in a4 or a6), g5=1 (in column i, 1 must be in i1, i2 or i3), g9=3, g8=5, g7=6, d7=5
2. a1 & b2 must = 4 or 7; eliminate from other cells in 3x3
3. h8 & i9 must = 7 or 8; eliminate from other cells in 3x3
Part 2:

4. Due to previous step, h7 & i7 must = 4 or 9; eliminate from other cells in row
5. In column-b, 2 must be in b7 or b9; eliminate from other cells in column
6. In row-8, 3 must be in d8 or f8; eliminate from a8 & b8
7. In column-c, 3 must be in c2 or c3; eliminate from More...
Part 3:

9. Simple elimination: c5=8, c1=1
10. a3 & b3 must = 8 or 9; eliminate from other cells in row
11. e3 & e7 must = 1 or 2; eliminate from other cells in column
12. Looking at i7= 4 or 9, can conclude b5 must = 7; proof: if i7=4, then i6=9, e6=8, e2=4 & e4=7; if i7=9, then More...
Part 4:

14. d5 & f5 must = 4 or 6; eliminate from other cells in 3x3
15. h1 & i1 must = 6 or 8; eliminate from other cells in row
16. a3 & a8 must = 8 or 9; eliminate 1 from a8
17. Simple elimination: f3=6, f5=4, d5=6, f1=9, d1=4, f2=5
Part 5:

18. Looking at e7 = 1 or 2, can conclude that i9=8; proof: if e7=1, then d2=1, i2=7 & i9=8; if e7=2, then b9=2 and i9=8
19. Simple elimination: h8=7, f9=7, h2=3, h3=5, h6=5, c2=2, e3=2, e7=1, a7=3... easy eliminations to finish

Thanks to Valy for pointing out step 18
Nice puzzle forgot to set timer---ooops
19.33 but did resort to Valy's assist at 46. Thanks!
That one really was tough. I usually print them out and work it out with pencil, paper and eraser.
heelo all ... 13:38 tonite
I read the comments first and saw dolphins so thought have to do this one now? great pic? but I do prefer to see them in their own natural world. I know that they do those tricks! in the wild but there they are not induced for anyone's pleasure other then their own, and it really is an amazing sight to see.
10:26 I found the tough a little easier than the hard 2nite. Until tommorrow................
18:40 - and several complete restart attempts. but had to guess top right corner (i-1 or 1-i?) as 7 or 8. Couldn't work out logic to get past this. Then it all fell into place.
I had no problems with this one and found it straightforward- apart from one guess very early on at about 25 cells filled- got the three bottom squares B2 E2 and H2 almost completely filled in first and then it was plain sailing.
Good night from Kiwiland!
Takes me 5min to 8min to put in possibilities. Then another 15min to 25min to solve ... no mistakes. Can't understand how anyone can do it under 10 minutes. Are you sub 10minute elites including the time to think before you start or filling in the possibilities?
I never take any time before I start, but sometimes I use the 'check moves' on the harder ones and sometimes switch off the 'allow incorrect moves'. The 'easy' just go straight into it. My times vary a lot, all depends on the day I've had.
Yea no guesses tonight!
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