Sudoku Puzzles

any bats in there?

5:48 Maen

A MESSAGE FROM CP, CANBERRA TO ALL SUDOKU PLAYERS IN CANBERRA

Canberra Sudokoists - come join some fellow addicts at Rodney's at Piallago at 2.30 on Tuesday 9th January. Table booked for CP, it'll be near the kids' playground. Partners, kids welcome. How about it Chrissy, Angry Ant, Angus and vk? Any others?

Maen - A brutal puzzle today.

Visited the Jenolan Caves--they're awe-inspiring. But the drive to get there requires a good dose of Dramamine.

Wow I just started this puzzle and couldn't find a single unique, even after filling in every cell with it's possibles. That's an unusual start.

This puzzle was a BOOGER to get started but pretty easy after that!

43:18

7:02
where is Batman?

Only one guess, turned out to be right, very easy after that. I still haven't learned how to choose my guesses correctly... oh well.

Neat cave.

Where are these caves located?

unfortuantely I haven't been able to look at this for more than 5 minutes at a time and keep loosing my train of thought. I actually haven't been able to fill in a single square with certainty. anyone know the first square they filled in and why?

couldn't do it without a guess, ah well, perhaps tomorrow the brain shall follow logic...

Well if you guess right at A8 the rest of it falls into place easily wtihout any advanced techniques. I just hate guessing

The Jenolan Caves are in Australia, fb, and well worth a visit if you're ever downunder. But the curvy road to get to the caves will make you lose your lunch ...

I used CS's hint to get through this one.
Nice stalagmites. My son's boy scout troop went spelunking this past October, and he had to crawl on his belly through some of the tunnels. Not my cup of tea, especially in the dark!

A proof for tough sudoku of 01 09 2007:

1) Start at 23 filled - the given puzzle. Unique Possibilities to 23 filled. (UP 23).
2a) fc on 2's: i6 == e6 -- e2 == a2 -- a9 == h9 forbids i7,g5=2
2b) Locked 3's at de3 forbids gi3=3
2c) Locked 5's a tef7 forbids ghi7=5
2d) fc on 9's: More...

Very little time pare down the proof. Certainly, some of my steps are not required. Probably less depth can be achieved.

Sorry about the typo's above
While driving my son's to wrestling practice, I realized that I included lots of extra steps in my proof. Here is a smaller proof:
(With some corrected typo's...!)
1) Start at 23 filled - the given puzzle. Unique Possibilities to 23 filled. (UP More...

Step 3b in my second proof is non-trivial.
It considers the following strong sets:
a2=24, h79=3, agh7=7, aghi7=3, hi1=3, h1g3=7.
It concludes: a1=4 == a7=37 forbids a7=4

The conclusion involves the use of a nested conditional forbidding chain. A forbidding matrix would probably More...

A typo in my explanation: rewrite

Since h7=2 forbids h7=37, we have an almost hidden pair 37 at ag7 or we have i7=3, but
if i7=3 ....

Wow that was quick! I submitted this one two days ago after our Saturday 6th January trip! Welcome back Gath!

Jenolan Caves - www.jenolancaves.org.au - are west of Sydney.

The Guide said the Orient Cave used to have bats (and we saw some bat bones in a stalagmite) but the high More...

That's 175 km west of Sydney! A pretty full day trip.

Hi everyone! ok must be off now.

Hi STEVE,
Your step 3b maybe start at a9...

I'm afraid I had to cheat but Kate's photo was worth it, its amazing the different colors of the stalagmite so beautiful.

When this photo started to come up, I thought that it was of two strange looking animals - the male in the foreground with pointy hat and flat beak giving something/one the glad eye. The rather untidy female is flouncing into an alcove in the background, her tail held high with indignation. Like a lot of optical illusion pictures, once you see one thing it's very hard to see anything else!

thanks ttt!
Indeed that is where it should start. I did not proofread before posting today, and it shows.
Sorry!

5:11 2007-03-09

A simple one. Took less than 25 mts.

Dec. 21, 2007.