Start Pause Reset
46 Comments Previous / NextHelp

Tough Sudoku for 1/October/2005


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

Sudoku Solving Techniques

Submitted by: sudoku lover

Indicate which comments you would like to be able to see

Wow - it's so still Friday afternoon here - you Australians are just so ahead of us! No wonder you can do these puzzles so fast. ha ha.
First time I solved the puzzle w/o guessing...didn't really believe it could be done!
Yeah! I got it without guessing, the second day in a row, i'm on a roll (or they're just really easy for tough ones).
Arguto e ben fatto - very nice
Simple! DO it less than 2mins.
Another '19->51' type, 8th since 09/11. It's the most common here and the simplest too. Try 09/11,14,15,18,19,23 and 30. We'll soon solve those ones in seconds (including proof writing)!
Good Morning from the U.S.

Yah, what a good puzzle - always a good way to start the day.

Have a great weekend everyone!

abiento, ciao, hasta luego, & aloha ;-D
gb, What do you mean by '19->51 type'? I'm getting better at these but still get stuck and have to guess on most of the tough ones. What's the secret to this one? Thanks!
no time, still using helps - fewer wbs (wild blind stabs) - is that the Golden Gate?
It's the Brooklyn Bridge.
Think it is the Brooklyn Bridge in New York City.
time didnt matter i finished it and enjoyed have a great w/end guys
Hi Madge,
this puzzle and his twins begin with 19 filled cells, after what performing easy eliminations give 51 filled cells.
Then a second step xwinglike gives 2 more cells.
Then a third step xwinglike gives complete solution. See http://brunogreco.free.fr/bazar/sudoku/10-01.htm
for a complete proof.
Thanks gb, I'm at the 51 filled cells. I'll check out the solution for help finding the xwings. Didn't see them earlier, but then it's Friday and my brain is fried! Thanks. again!!
gb, can you help a bit more? I found the 1st xwing (duh). But help me understand the next step. I'm not picking up on the code that you use. It says: 'Look at 6 in Bb2 : whether it's in c2, in which e2=5%row, or it's in b1, in which b4=5%col : e4=8%cell.' I understand that the result of this More...
Well madge,
Have you read the notation conventions? I assume that you did but here are details :
In Blockb2, remain two empty cells b1 and c2 , each one having 5 or 6 as only possible value, right? Then 6 in this block is either in b1 or c2.
If c2=6, e2=5%row (this means that e2 is the More...
So in both cases e4=8.
Hope this helps and that my bad english won't help you from understanding.
Got stuck with 25 to go and made a guess. Guessed right??? Does that count? 25:06
It's 00:01 in the UK and i've solved the tough one - don't know how long i took!!!

Have a great weekend everyone
it took me 25:33 to solve it !!
22:44 - and I was never stuck - just kept plugging along! gb, you're right; soon we'll be doing the 19->51 type in seconds :-) I know you label cells as in chess, but what does that mean? Where are the numbers and letters - top to bottom, left to right, etc.? By the way, no worry, your English is fine. I'm just glad this site isn't in French ;-)
10:52 Well, my work is done for today. Now what am I going to do. Suppose I should've thought of that before I started so early this morning. Is there a Sudokuics Anonymous?
go the cowboys!!
sorry kids, i'll be finished this bloody thing soon
happy honeymoon Gath - hope you check this site if you get bored!!
6:49, Hi K, from brissie, glad to see you support the right Rugby Team. Raah for the Cowboys to win on Sunday.
Well someones gotta cheer for the tigers! This place will be hopping tomorrow!
What a relief to succeed consecutively for two days after being humbled on 28/9 and 29/9.
Hi Katrina and Yvonne. My two favourite teams do battle tomorrow; have to wear two hats (interchangeable of course). I have all the camels and locusts over to watch game at my place so will have my Sudoku fix bright and early to give me time to prepare the consumables.
Regards Geoff.
I miss you so much my dear
28:35 but i think i cheated as i looked at what gb had to say and just put a 6 in c2. it didn't make any sense at all to me (get lost with all those % signs - don't know what they mean), i'm not into maths from above year 11, and i did that 30 years ago! i can still do the puzzles though, usually gotta guess on tough. have fun all.
hi pam,
i'm sorry so I repost explanation! This notation '%' is andrei's own and means 'because of its':
e4=7%cell; (empty comment meaning that the only possibility for e4 is 7).
e4=7 %Row; (e4 is the only possibility for 7 in its row R4).
e4=7 %Col; (e4 is the only possibility for 7 in its column Ce).
e4=7 %Block; (e4 is the only possibility for 7 in its block Be5).
hi jh,
notations remembered at http://brunogreco.free.fr/bazar/sudoku/.
They're due to andrei who introduced them on comments below 09/16's tough puzzle.
salut a tout salut a toute je vous souhaite a tous de jouer comme un pied qui pue la fondue!!!!!!!!
hihihihi hohohohoh hahahahaha
It is a great feeling first time I got the hard one...
love it love it-got the hang of it now-12mins
thanks to angusj for explaining the remote pair
17:53 one fc
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