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jack02 · Joined: 08 Jan 2013 Posts: 5

I get a "unique rectangle" 0f 1/6 based on E3,E7,F7,F3. Removing the 1/6 at E3 (because of E7,F7,F3) leaving the 5 results in a valid solution.
However if you assume either 1 or 6 at E3 this also results in valid solutions.
Anyone cofirm this?

arkietech · Posted: Tue Jan 08, 2013 2:01 pm Post subject:

All I needed was basics. Locked cells only.

jack02 · Joined: 08 Jan 2013 Posts: 5

OK - but see below 3 solutions...

9 4 1 6 5 8 7 2 3
5 2 8 7 3 9 4 1 6
6 3 7 1 2 4 9 5 8
2 7 3 8 6 1 5 4 9
4 1 5 9 7 3 6 8 2
8 9 6 5 4 2 1 3 7
7 5 4 2 8 6 3 9 1
3 8 9 4 1 7 2 6 5
1 6 2 3 9 5 8 7 4

-or-

9 1 4 6 5 8 7 2 3
5 2 8 7 3 9 4 1 6
6 3 7 1 2 4 9 5 8
2 7 3 8 6 1 5 4 9
4 5 1 9 7 3 6 8 2
8 9 6 5 4 2 1 3 7
7 4 5 2 8 6 3 9 1
3 8 9 4 1 7 2 6 5
1 6 2 3 9 5 8 7 4

-or-

9 1 4 6 5 8 7 2 3
5 2 8 7 3 9 4 1 6
6 3 7 1 2 4 9 5 8
2 7 3 8 6 1 5 4 9
4 5 6 9 7 3 1 8 2
8 9 1 5 4 2 6 3 7
7 4 5 2 8 6 3 9 1
3 8 9 4 1 7 2 6 5
1 6 2 3 9 5 8 7 4

kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

This puzzle has given me fits!! I started with pen/ink and made a mistake so started over. Wasn't paying close attention, arrived at a solution, but don't remember how (maybe an XY, not sure). xx to online and solved it using basics only. Haven't been able to duplicate that one at all after several retries. Eventually came across a 467 XY pivot r6c3 yielding r9c1<>6 leading to a solution that I can duplicate at will. As for multiple solutions - haven't found any yet, but never know on this one.

arkietech · Posted: Tue Jan 08, 2013 6:38 pm Post subject:

kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

arkietech, help me sort things out. jack02 listed three solutions and you said the third(last) is valid. You also said you solved using basics only. Is your solution in agreement with his third solution? Whether there is agreement or not, can you indicate, in some way, how basics did it for you?

The online daily solver says my solution using a 467 XY wing is correct. I assume you and jack02 also used that solver and it says your solutions are correct. This suggests a puzzle having multiple solutions. So--just how does the daily solver handle a multi-solution puzzle?

Lastly, what is the definitive word on todays puzzle?

kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

I forgot an important fact--my solution does not agree with jack02's third solution.

Marty R. · Posted: Tue Jan 08, 2013 10:33 pm Post subject:

First, from the FAQs:

"Q3. Does a Sudoku have more than one solution?

Properly formed Sudokus (as available from the Daily Sudoku) always have only one solution. In our view, a Sudoku with more than one solution is not properly formed, but of course puzzles from other sources may have multiple answers."

I played it online, needed basics only and got this solution:

arkietech · Posted: Tue Jan 08, 2013 10:44 pm Post subject: Re: Jan 7 VH

jack02 · Joined: 08 Jan 2013 Posts: 5

Looks to me like all three solutions contain all the clues in the correct postitions as well as uniquely contain each number 1-9 in rows, columns and boxes.
I know that is not supposed to happen but here it is.

keith · Posted: Thu Jan 10, 2013 12:34 am Post subject: Re: Jan 07 has 3 solutions

Marty R. · Posted: Thu Jan 10, 2013 12:56 am Post subject:

If I bring up the puzzle, immediately click Auto Sweep and only type in the answers that show as one possibility left in a cell, I get the following grid:

jack02 · Joined: 08 Jan 2013 Posts: 5

Keith,
For me puzzel resolved to:
9 14 14 6 5 8 7 2 3
5 2 8 7 3 9 4 1 6
6 3 7 1 2 4 9 5 8
2 7 3 8 6 1 5 4 9
4 15 156 9 7 3 16 8 2
8 9 16 5 4 2 16 3 7
7 45 45 2 8 6 3 9 1
3 8 9 4 1 7 2 6 5
1 6 2 3 9 5 8 7 4

At first I was stymied but the 16 combo at box 4 and 6 looked like a deadly pattern so I eliminated leaving the 5, and from there quickly solved.
However I'd never acually tried the "unique rectangle" strategy before, so I decided to just try plugging in the other two values to test. Both the 1 and the 6 also resolved to valid solutions.

Marty R. · Posted: Thu Jan 10, 2013 4:16 pm Post subject:

Converting jack02's position to grid style.

arkietech · Posted: Thu Jan 10, 2013 4:53 pm Post subject:

keith · Posted: Thu Jan 10, 2013 5:04 pm Post subject:

In the original puzzle R6C3 is given as 1 and it has a unique solution.

Keith

jack02 · Joined: 08 Jan 2013 Posts: 5

I'm not sure if I should feel seriously stupid or slightly clueless (i.e. missing a Clue!)...
Thanks for the Help!

Marty R. · Posted: Fri Jan 11, 2013 2:48 am Post subject: