The New Sudoku Players' Forum

[dneely]

004530807
000004035
095008460
100405200
500010604
042900513
420800356
000650040
956040700

I got to this point and the computer says the next move is to put a 1 in column 2 row 1. I don't see why a 1 couldn't go there or column 2 row 2 or column 3 row 2. The neighbor got it so it must be me.

[sweetbix]

The only places for a 1 in row 1 are in c1 or c2 or c6 or c8.

There's already a 1 in other rows of c1 and c8. It looks to me as if the 1 could go in r1c2 or r1c6.

Did you put the 1 in r5c5 in the right place?

[QBasicMac]

the computer says

You didn't post your pencilmarks. Assuming you made no pencilmark erasures, this is what you have:

Code: Select all

+------------------+------------------+---------------+
| 26    16    4    | 5    3     1269  | 8   29   7    |
| 2678  1678  178  | 127  2679  4     | 19  3    5    |
| 237   9     5    | 127  27    8     | 4   6    12   |
+------------------+------------------+---------------+
| 1     3678  3789 | 4    678   5     | 2   789  89   |
| 5     378   3789 | 237  1     237   | 6   789  4    |
| 678   4     2    | 9    678   67    | 5   1    3    |
+------------------+------------------+---------------+
| 4     2     17   | 8    79    179   | 3   5    6    |
| 378   1378  1378 | 6    5     12379 | 19  4    1289 |
| 9     5     6    | 123  4     123   | 7   28   128  |
+------------------+------------------+---------------+


In which case, I don't know why your program didn't recommend to place a 3 at r3c1. Why? Because it is the only 3 in row 3.

Try that and continue. Ignore your program. What is it's name? You can use my program at www.SuDoku.funurl.com (SSP3) to keep pencilmarks straight. (There are many others). It will even give hints if you are taking too long and are missing something simple. But I just use it as a scratch pad. (P.S. Ignore my site if you know nothing of ZIP and Directories (folders).

Anyway, if you want more hints, see below (after trying)





Locked candidate 7 in box 1
See? All 7's in box 1 are in row 2. Thus a 7 must go into one of those 3 cells. Erase 7's from r2c45 as they are impossible.

Locked candidate 3 in box 5
Locked candidate 3 in box 7
Locked candidate 8 in box 7
Locked candidate 9 in box 9
Locked candidate 2 in col 5
This is interesting. Since all the 2's in column 5 fall into box 2, this means no other 2's can be in box 2. Erase 2's from r23c4 and r1c6. That gets you to here:

Code: Select all

+------------------+---------------+--------------+
| 26    16    4    | 5    3    169 | 8   29   7   |
| 2678  1678  178  | 1    269  4   | 19  3    5   |
| 3     9     5    | 17   27   8   | 4   6    12  |
+------------------+---------------+--------------+
| 1     3678  3789 | 4    678  5   | 2   789  89  |
| 5     78    789  | 237  1    237 | 6   789  4   |
| 678   4     2    | 9    678  67  | 5   1    3   |
+------------------+---------------+--------------+
| 4     2     17   | 8    79   179 | 3   5    6   |
| 78    1378  1378 | 6    5    127 | 19  4    129 |
| 9     5     6    | 123  4    123 | 7   28   128 |
+------------------+---------------+--------------+


There is nothing but simple singles after this.

Mac

[QBasicMac]

P.S. I accidentally erased the wrong 2's in my post. I noticed that about 3 minutes later and immediately patched my post. If you already got my first reply and are mixed up, sorry! Otherwise, it should be correct now.

Mac

After correcting again my comment to Erase 2's from r23c4 and r1c6.

Haste makes waste

[QBasicMac]

Did you put the 1 in r5c5 in the right place?

Yep, you probably are on the true correct path, namely the puzzle as posted is not correct. DNeely probably copied by hand and got the positions mixed up.

If THAT is the case, the problem with the program being used is that it does not produce current status in a form suitable for posting. A simple copy/paste is better than re-typing. I can seldom re-type a puzzle correctly (as you can guess by all my corrections above)

Mac

[sweetbix]

The 1 in r2c4 eliminates the 1s in r2c2 and r2c3. Therefore the 1 must go in r1c2.

[QBasicMac]

The 1 in r2c4 eliminates the 1s in r2c2 and r2c3. Therefore the 1 must go in r1c2.

True, but easier to see is to simply place the 1 in r2c4 as it is the only pencilmark in that cell. Now c1c2 has the only 1 in box 1.

Actually, there are now nothing but singles. No logic required.

Mac

[sweetbix]

I don't see why a 1 couldn't go there or column 2 row 2 or column 3 row 2.

dneely, I'm sorry if my answer was confusing. Iif you are still looking at this puzzle here is a simpler answer to your original question.

There is only one place for a 3 in box 1 = r3c1
Now the 7s must go in row 2 in box 1 so remove them from r2 in box 2
Now in box 2 you have a triple 12 127 27. Since there are only three numbers for these three cells remove them from other cells in box 2
Now you have only one 2 in column 5 = r3c5
Now you have only one 1 in box 2 = r2c4
Now you have only one 1 in box 1 = r2c1

It's funny that your computer would jump straight to r2c1 when there are the other steps to do first.

[Cec]

"..Now in box 2 you have a triple 12 127 27. Since there are only three numbers for these three cells remove them from other cells in box 2
Now you have only one 2 in column 5 = r2c5.."

Hi Sweetbix,
With this naked triple [127] occuring in cells r2c4, r3c4 and r3c5 then all other candidate 2's can be excluded from box2. This leaves r3c5 as the only placement for the 2 in column 5.

Cec

[sweetbix]

Thanks Cec. I corrected my mistake.