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Tough Sudoku for 27/January/2006

                 
                 
                 
                 
                 
                 
                 
                 
                 

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

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Submitted by: Gath

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14:58
Tough!guesses twice!
I got to 51 filled by simple eliminations. After that, it was one long and convoluted FC before simple to the end. No Y wings found.
10:06... hmmm
Good maen to all just new at this could someone please tell me what is refered to as y wing
Ah, that wasn't so tough!

new to tough puzzles. what is a y wing?
Yea wot on earth is a Y wing?
I found no Y wing on this one either. At 51 filled, I excluded 3 from d5 with the following chain:
d5=3: pair 46 =>h5=5. d9=7%cell:f9=9%cell:d1=9%box:b1=4%box:h1 =1%cell:g6=1%box:g4=7%box This leaves me with no 7 possible in box e5.
This was very messy. Please someone show a better way. Thanks!
Happy MAEN to one and all!
11.18,not to bad
this is sooooo fun. i wish i could get some more.
Hi everyone!
MeMee_912 From Minnesota, go to the Archives up at the top and you will find lots and lots more!!
11:55 This one just flowed- I didn't find any FCs - only triples etc. Unless I made a serendipitous mistake, this puzzle does not deserve the TOUGH categorisation.
18:56
The castle at St Andrew's in Scotland has this ROCK seat hanging over the edge of a parapet. The seat has a hole in the middle. Much prefer indoor plumbing!
wasn't going to attempt a tough, but loved my visit to Cardiff Castle, sooooo, now I have to stay up late and to it. thanks, guys. St. Andrews is my favorite town in the whole world. spent a lovely summer there in 1979 and visited again in 1984.
Yes I got totally stuck at 51 cells filled. Steve from Ohio's system works (although for d1=9 read e1=9). I'd love to have one of you guys who say it was easy let us have a proof... interesting that no one else has done so apart from Steve.
Goodness. I think they need to warn you that tough is really, really tough. I don't think I have any hairs left on the top of my noggin. Oh well. Papa always wanted me to push myself. So here I am pushing myself. Maybe next I'll go and see what lies on the outside world....no...i'm safer in More...
Steve/Ohio - very good! Peter/Carterton - I agree. The only way I could solve this one was to pick a likely pair, allow incorrect moves, and try each of them until one didn't work - not nice....(at 51, though, I found used a FC to eliminate 2 in e1, leading to d1=2....but then I was stuck at 52. See you later!
Marjorie Jane - what's a lutefisk?
'Lutefisk' is an infamous Norwegian dish composed of fish soaked in lye- pasted from Google!

Thanks for your support Christina!
Hmmmmm - this doesn't sound like a recipe for the uninitiated.
Thanks for the edit Peter. Sorry about the error. I think that often if one misses a possiblity, a tough puzzle could become easy. If it becomes impossible because of the error, one finds the error. If it becomes easy, though, one does not uncover the fortuitous 'mistake'. (Is it really a mistake if it solves the puzzle?) Hmmm.
26:02 Fine by me. Hi to all
Steve, I think you win the prize so far. This was a frustrating puzzle in not having at least one clean FC. There was no 259 wing. In Be2 where it would have had to be centered, 6's kept it from happening.
1- a3=3, d3=8, b2=6, f2=3, h2=2, i2=8, c3=2
2- triple 36/69/369 in col.h/Bh8, i7=7, g7=8, g9=2
3- remove 9 from a6, c6. i6=9
4- remove 9 from b8, c7, c7=6... to 51 filled
5- Whatever you choose in d5 (3 or 5) leads to d1=2
6- Whatever you choose in d6 (5 or 7) leads to c6=4, 54 More...
I really liked this puzzle. I was able to find several forbidding chain eliminations to solve it logically.
14:28
You were right! I went back to prove you wrong and found you were right. I'm not sure. This was the logic I followed.

Setting up:
Started with 8s placing the confirmed 8s in Be2 and Bh2 , 7s possibilities, b2=6 then 6s possibilities, Possibilities for 5s
f7=4 then 4s possibilities, More...
c5=9, c7=6, a9=1 Eliminate 4s in col a then 5s in Bb5, b4=1, b5=8, b9=5, c9=8, b8=7, d8=6, h8=9, h7=3, h9=6, d7=1, a7=9, a8=4, f5=1, c1=7,

51 filled:
FC If f4= 5 , f9 = 7 , d5=3 & d9= 3 impossible Therefore f5 = 7 or 6 therefore the 5s in col f must be in Be2, therefore d1 doesnot More...
Valy is much more succint, though it looks like he had a couple more FCs.
no idea what a y wing is either - this one took me 26:52, but i never tried a tough before
9:30
08:51
39:41
17:03..09/29/06

SE=6.6
05/Sep/10 9:57 AM
17:00.
27/Jun/19 1:58 PM
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