Start Pause Reset
37 Comments Previous / NextHelp

Tough Sudoku for 20/July/2006


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

  1 2 3 4 5 6 7 8 9
Check out the latest post in the Sudoku Forum

Welcome to the Sudoku Forums!

Submitted by: Gath

Indicate which comments you would like to be able to see

Hello Deb
A lovely smiling photo
Hello Deb 13:41 with a couple mistakes
Just sitting up watching Big Brother, doin my sudoku, it's so cold here I think it would be lucky to be one degrees. Come on Summer hurry and thaw me.
Always nice to see a smile from Deb. Hope everyone gets a smile today. Happy day, all!
Hi deb, good to see who we get to chat to in pictures.Like your scarf, did you knit it?I make lots of them,have made over 300 since last year. Now I'm making baby gifts for quite a few friends having their first grandchildren.Will be a while yet for me, none of my three boys are serious yet(still in college).
Good Maen Deb and everyone else! Nice finish to the day to see a beautiful smiling lass!
Hi Deb! thank goodness for possibilities and auto remove them, too. Otherwise, I'd still be looking for most of the puzzles. I wish I could automatically remove possibilities when I'm working on paper! Great site, Gath, if I haven't said that already.
10:49 with too many guesses.
Hello Deb..lovely smile..sort of contagious!nice way to end my day
Hello Deb,

If you are ever out this way, come visit and tell my family about yours!
16.50 Good Maen Deb. Nice to meet you at last.
Hi Deb! And g'maEn, all.
18:41 - a tough one tonight. Nice to meet you Deb.
LINDA fr Melbourne - How come you get to use your real name? There are a great many Linda's here. We should start a LINDA CLUB. LOL
Who's your favorite and least favorite on Big Brother? I love mindless TV...escape from my reality to watch (not so) reality tv! It's 98 here today and thunderstorm about 1 block over.
Nice to put a face with a name...great smile!
Hi, Deb. Sending a smile back to you. :)
Hello Deb! Happy Sudoku Day to you in Brisbane.
HI DEB! It is nice to put a face to a name. How about a Deb club too? Have a great day everyone. Good mAen to you.
5:49 ... but I guessed a lot today. Seemed tougher than usual. very difficult to find the hidden pairs (or triples) so I just guessed.
Hi Deb, nice to see a face for a name. Great smile.
Hi Deb, nice to see you. It's worth the agony of tough to see your smile.
Hi Deb from Brisbane.
I do not have a proof for this one that is worth publishing... if anyone has a well reasoned proof for this puzzle, I would be very interested.
Had to see Deb from Brisbane - nice to put a pretty face with all the good jokes and personality
Deb, you are brave to post your picture; I am camera shy! Maybe it's because you photograph well!
Steve, I am new to this site and have found your posts helpful to the extent that I understand them. To that end, is there a faq sheet someplace that explains the shorthand you use in your proofs?

Same subject (new here and new to the jargon), would you be kind enough to tell me the meaning of Maen or maEn?

good mAen = good Afternoon
I'm sure you'll figure out the rest :))
Hi Mike -
Check proofs link at bottom of page.

Matrices, though, are an invention of Andrei not yet included in the proofs link. Explanation of these can only be found delving through the archives. Some day I may create a web page, but not enough time yet.

It's unsportsmanlike, but I'm glad to see no one had a nice neat proof for this one!

Hello, Deb. Glad I hung in to see your face.
9:16 using a new method for hard puzzles, normally would have guessed most of it

1) hidden pair @ d7,e8 = 13 UP 27
2) examine possible hidden 1-3 pairs left in position ...
there are 13!! of them, now I know I'm on to something,
coincidences like that just don't happen in real life!
3) a lot of possibilities, I begin to doubt -- but wait,
I cannot possibly compete with the proof that Pat has submitted, but using logic that is perhaps less sound, here goes:

1) Start at 23 filled - the given puzzle. Unique Possibilities to 24 filled. (UP 24).
2) Hidden pair 13 at d7e8 forbids d7=457 and e8=5. UP 27
3a) Locked 3's More...
Pat, you're a genius!
Maybe you should keep this algorithm to yourself, otherwise tough sudokus will cease to be a challenge.
Aug. 24, 2007.
25/Aug/07 5:35 AM

05/Sep/10 9:22 PM
15/Nov/19 7:39 PM
Please Log in to post a comment.

Not a member? Joining is quick and free. As a member you get heaps of benefits.

Join Now Login