Tough Sudoku for 18/July/2006

easy today

Is that a nude sudoku player from Friday?? LOST & PONDERING!!

Maen - no backtracking - but it still took me 20 minutes pretty much filling in as fast as I could. I don't quite understand how people can click so fast. Maybe you guys don't fill in the possibilities?

7:27 pretty easy tough Maen

No man is an island??

Hi everyone

Forgot the timer...again, but figure around 15-17 min. Where was that photo taken?

'You can't appreciate home until you have left it.'

Good puzzle. Pretty much worked itself, but took 14 minutes. Is that an alien sudoku solver? Looks all silvery to me.

19:50. But I cheated. G'maEn, all.

15:27 A bit tricky!

Was he standing there so long that he turned to stone?

scary man. should keep the gulls away!

For most of the puzzle straight!End play more difficult.Instead of looking for hiden imposibilities,I prefered to check between two choices!Becaue of the advanced stage,easily concluded to the solution

Does not look too tough today:
1) UP to 26.
2)e89=3 forbids e123=3.
3)d789=7 forbids d3=7.
4)de3=49 forbids 49 in the rest of R3 and Be2.
5)UP to 44.
6)e12=8 forbids e789=8.
7)Up to 48.
8) FC in 7s: d7==d8--hi8==h9--h5==b5 forbids b7=7.
9)Up to 81.

Islands where?

1) Start at 22 filled - the given puzzle. Unique Possibilities to 26 filled. (UP 26).
2) Hidden pair 68 at e12 forbids e789=8, e12=1349. UP 27
3) Locked 1's at f12 forbids f45=1 UP 48
4) fc on 7's: b5 == h5 -- h9 == ab9 forbids b78=7
sets: 5. Max depth 2. rating: .07. Very easy!

I don't follow your logic below. Please explain.

1) Start at 22 filled - the given puzzle. Unique Possibilities to 26 filled. (UP 26).
2) Hidden pair 68 at e12 forbids e789=8, e12=1349. UP 27
3) Locked 1's at f12 forbids f45=1 UP 48
4) fc on 7's: b5 == h5 -- h9 == ab9 forbids b78=7
sets: 5. Max depth 2. rating: .07. Very easy!

18.16 Good for me! maEn.

If I were a statute, I think I would want to be gazing out to sea.

7:44

8:05 after setup. Probably fastest tough ever. But seemed like an easy one! What is that weird picture?

12:37
Sculpture by the Sea?

HI Jack!

I am not sure what part of the proof you do not understand?
1) Given puzzle has 22 candidates unique determined. 4 more unique determinations using singletons at either row, columns, boxes or cells.
2) The 6's in column e to e12, while the 8's in box be2 are limited to e12. This two strong sets forbid the 8's in the rest of column e and forbid all items not 6 or 8 from cells e12. These elimination then give us one more singleton:
e7=4.
3) Now, the 1's in box be2 are limited 2 just 2 locations f12, which forbids 1 from the rest of row f. This then gives us singletons in rows, columns, boxes and cells to 48 filled.
4) If b5=7 then clearly b78<>7.
If b5<>7, then h5=7 then h9<>7, but then either a9 or b9 must be 7. a9=7 forbids b78=7 and b9=7 forbids b78=7. Thus, one concludes that b78 cannot be 7. Now, we have singletons in rows, columns, boxes or cells to 81 filled.

23:04

Hi, Pat from Milwaukee
I posted my reply to you comments on yesterday's puzzle. Just in case you don't go back there, I am repeating it here:
'I did the puzzle again and found out you were right! f4=4 and f8-4 is only a weak set. My mistake was probably at the step 3), where I filled in two cells incorrectly (UP should have been 37 instead of 39 as I'd posted), making that set strong. So the case is this detective's errouneous ground work resulting in an invalid fs. Sorry.'

forgot to set the timer but used check moves to help so feel I've cheated today. Is our stoned friend looking for money on the ground?

10.48 first time on tough for a long time but have time as it is too hot for anything energetic

5:09

to Steve from OH
an interesting and perhaps common pattern behind
your FC. Looks like an X-Wing, but with one corner
(ab9) using a box-row combination where the eliminations are limited to the common box and column. Call it a Q-Wing!

yes tammy, sculpture by the sea :)
by an icelander called Steinunn Thorarinsdottir
(phew)

21:15

Aug. 24, 2007.

SE=6.7

15:55.