Sudoku Puzzles

That makes a change from Scotland & Peru, a photo of Spain. Very rugged looking.
fi, I usually do your photo as a jigsaw when there is one of Scotland.

Tallest in Spain?

looks like an old, dormant volcano...

A brilliant snow covered peak!!

a volcano??what i see is not snow then??
ok i'll google it anyway..

To Pat.
Thanks for looking at my “UR that wasn’t” yesterday. Sometimes we think we understand something when in fact we don’t. I don’t think I’m the only one who failed to realize that the four cells needed to be in two blocks, not four. Maybe now I have finally got the picture with UR’s .

To Jeff,
Thanks for offering to put my partial completed sudoku up on your space. With Pat’s explanation, I see that I was wrong, so there is no longer any value in doing that, but I do agree that it would be helpful to discussion if it were possible to capture and post a screen. Perhaps Gath can consider the idea.

Nothing harder than a xy wing?
Great picture!

18:17 Pretty mountain

Start at 23, UP 46.
1. xy wing, elim i7=2. UP 48
2. xy wing, elim a2=6. UP 81.
Easiest tough in a long time.

1. Start at 23. UP 28.
2. Locked 7s in row 9, elim in Bh8; i9=7%col
3. Triple: i578=238, elim in col
4. Locked 3s in Bh2, elim in col; UP 45
5. Pair: b7=c7=68, elim in box and row; UP 46
6. Pair: b1=c1=58, elim in box
7. Fc: If f5=3, f7=2 => i7=3; If f5=8i5=2 => i7=3; UP 48
8. Fc: If b4=2, b2=6 => a2=4; If b4=9, a5=6 => a2=4 UP 81

Hopefully, the occasional diabolical tough, or at least suitably difficult tough, will grace this site again!

14:52 Easy one today.

To Pat. Thank you for justifying and confirming what I've maintained all along, that AUR is a valid technique.

To Meg. Sorry I didn't get back to you but I've only just looked at yesterday's comments. Glad to see it was answered for you.

23:29

If the AUR discussion is once again to be had...
I will simply repeat last conclusion after Kaz straightened me out:
If it is assumed that Sudoku has the rule (axiom?): Each puzzle must have exactly one solution, then AUR is valid.
Since this is generally assumed... conclusion is obvious.

To anyone interested, a long time ago I promised gb a depth 4 solution to the puzzle of 02/28/06. I emailed the proof to him, but he has since disappeared. I have decided to publish something close to that proof in the archives - not sure I remembered it exactly...

BTW - I noticed recently a few voices from the past:
Great to here again from: Sundance and Christine!
Hopefully, we will continue to hear from some of the past regulars to this site!

If Andrei, gb, DJ, Vali, etc. still frequent this site, it would be very nice to read posts from you More...

Some things never improve - like my spelling... hear would be perhaps better suited above.

Good mAen to all! Nice picture! Obviously part of the Pyrenees. Don't know if it's the highest HalT, but I do know they have peaks in the 9 to 10 thousand foot range.

Challenging as a jigsaw puzzle.

Good maeN all
hello fi, your 'cotton flower'seems be a 'linaigrette' I see such flower only dried! I try to see this flower in Alp but without success! Google Linaigrette wikipedia and you see some pics very clear.

alriight! i'm getting faster at guessing... jk

maEn all

Majestic.

7.55 i enjoyed this one

Although I feel I am coming in after hearing only part of the discussion, there is sometimes more than one solution. I sometimes print puzzles out and do them off line and I have come to a different solution than the one shown. I have rechecked and rechecked it, and I am certain that I am correct. It always (so far) involves the same two numbers that can be interchanged in serveral of the blocks.

Easy puzzle today, 8:36 after setup, done at end of long day at work followed by an exercise class! Nice mountain. Dan, we'll have to get some photos of Mount Rainier up there, no?

mount in tenerife?look like valcano sleeping. nice picture

Hi Linda - Please let us know when you have found multiple solutions. I have not seen a puzzle that could possibly have two solutions at this site yet - as I have always, even when using UR's, comleted an alternate proof. Of course, it is possible that two solutions existed on a puzzle I either More...

done.

Oct. 5, 2007.

SE=4.2