Sudoku

[Kungfuzed]

I'm really stuck on this one. I bought a sudoku calandar that gives a new puzzle every day and have been falling behind. I'm stuck on January 4th. Here's what I've got so far:

| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 4 1 _ | 2 5 9 | 3 _ _ |
| _ _ _ | _ 81 | 2 _ _ |
| 8 2 _ | _ _ _ | 9 _ _ |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| _ _ 8 | _ 2 4 | _ 9 _ |
| 2 _ 1 | _ 9 5 | _ _ 3 |
| 6 9 _ | _ 1 7 | _ _ 2 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 5 _ _ | 1 _ _ | 4 7 9 |
| _ _ _ | 9 4 _ | 5 2 _ |
| _ _ _ | 5 7 _ | _ 3 6 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |

It doesn't look so legible but I'm just hand typing it in. The numbers I filled in are in red. The answers are at the back of the calandar but I won't learn how to solve this by cheating. I've read some tips and strategies on other websites but they don't seem to apply to this paticular puzzle, unless I'm just blind. They say that these things can be solved with logic alone and no guessing. Anyone got any hints or tips for me?

[Green Gaia]

HA! I'm working on my own puzzle at the moment. I'm pretty new to doing Sudoku, so I'm likely not much help. But good luck!

[wizanda]

Use Deduction, work out which number can't go there, as it is already in another line....
Don't write any in ever, until you are 100% certain....mark all numbers in the boxes that it could be and then eliminate each numbers, you make certain of through deduction and then rub it out as you know it isn’t one of them, so you are left with just one possibility.
When it is just one number in a box left and it will add up along the lines, in the boxes etc and is correct, add it…..

Else if you go adding numbers that are possibilities…then you constantly have to go over the whole thing again.
It really is make sure it is right 1st time, all the way through…

Carol vorderman has written some excellent guides….on extra techniques of elimination and deduction that really help.

[Kungfuzed]

Originally Posted by wizanda

Use Deduction, work out which number can't go there, as it is already in another line....
Don't write any in ever, until you are 100% certain....mark all numbers in the boxes that it could be and then eliminate each numbers, you make certain of through deduction and then rub it out as you know it isn’t one of them, so you are left with just one possibility.
When it is just one number in a box left and it will add up along the lines, in the boxes etc and is correct, add it…..

Else if you go adding numbers that are possibilities…then you constantly have to go over the whole thing again.
It really is make sure it is right 1st time, all the way through…

Carol vorderman has written some excellent guides….on extra techniques of elimination and deduction that really help.

I'm trying to do this the same way I do crossword puzzles, with an ink pen. I've been trying to do some elimination in my head and so far there's two or more possibilities in each box. I might have to eventually give in and use a pencil.

[SoyLeche]

I was able to get it done - so it is possible. I don't see any mistakes in what you have done yet. Just keep going at it

[lilithu]

Originally Posted by Kungfuzed

I'm really stuck on this one. I bought a sudoku calandar that gives a new puzzle every day and have been falling behind. I'm stuck on January 4th. Here's what I've got so far:

| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 4 1 _ | 2 5 9 | 3 _ _ |
| _ _ _ | _ 81 | 2 _ _ |
| 8 2 _ | _ _ _ | 9 _ _ |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| _ _ 8 | _ 2 4 | _ 9 _ |
| 2 _ 1 | _ 9 5 | _ _ 3 |
| 6 9 _ | _ 1 7 | _ _ 2 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 5 _ _ | 1 _ _ | 4 7 9 |
| _ _ _ | 9 4 _ | 5 2 _ |
| _ _ _ | 5 7 _ | _ 3 6 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |

It doesn't look so legible but I'm just hand typing it in. The numbers I filled in are in red. The answers are at the back of the calandar but I won't learn how to solve this by cheating. I've read some tips and strategies on other websites but they don't seem to apply to this paticular puzzle, unless I'm just blind. They say that these things can be solved with logic alone and no guessing. Anyone got any hints or tips for me?

Hi Kungfuzed,

I think that when people start these puzzles the natural inclination is to look at the numbers that are there and then try to deduce what else you can fill in. That's perhaps the most straight-forward way to approach it but may not by itself be enough to solve the puzzle. Another way to approach it is to look to see what isn't there. You know that each row and each column and each box must have 1,2,3,4,5,6,7,8,9. So look for rows or columns or boxes in which a lot of the numbers have been filled in but some are still missing. Identify the missing numbers and then see if you can deduce where they belong.

For example, the first vertical column in the last column of boxes, reading from top to bottom you have: 3,2,9,_,_,_,4,5,_. The numbers that are missing are 1,6,7,8. Now, where could they go? You know that 6&7 cannot go in the last spot at the bottom because there is already a 6 & a 7 in that box (and a 7 in the same row). And you know that 6&7 cannot go in the bottom spot of the middle box because there is already a 6 & a 7 in that row. That means that 6&7 must go in either of the two top positions of the middle box. There isn't enough information yet to figure out which one goes where, but all is not lost. We know from this that the two remaining positions that you ruled out must contain either a 1 or an 8. Well, the bottom spot of the middle box can't contain a 1 because there's already a 1 in that row, so that box must contain the 8. Which means that the bottom spot of the bottom box must contain the 1. Looking at the rest of the bottom right box, only one spot is left and only one number is left so that must contain an 8. Now we have 2 out of the three 8s in the right column of boxes, leaving only the top right box. By process of elimination, we know that the last 8 must go in the middle column, top row.

| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 4 1 _ | 2 5 9 | 3 8 _ |
| _ _ _ | _ 8 1 | 2 _ _ |
| 8 2 _ | _ _ _ | 9 _ _ |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| _ _ 8 | _ 2 4 | _ 9 _ |
| 2 _ 1 | _ 9 5 | _ _ 3 |
| 6 9 _ | _ 1 7 | 8 _ 2 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 5 _ _ | 1 _ _ | 4 7 9 |
| _ _ _ | 9 4 _ | 5 2 8 |
| _ _ _ | 5 7 _ | 1 3 6 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |

So that would be my advice. Don't just look at what's already there but also look at what's not there. I'll leave you to do the rest.

[Shadow Wolf]

If I didn't have to leave for work in 20 minutes, I would solve it. When I get home, if it still remains unsolved, I will finish it.

[Shadow Wolf]

| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 4 1 6 | 2 5 9 | 3 8 7 |
| _ _ _ | _ 8 1 | 2 _ _ |
| 8 2 _ | _ _ _ | 9 _ _ |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| _ _ 8 | _ 2 4 | _ 9 1|
| 2 _ 1 | _ 9 5 | _ _ 3 |
| 6 9 _ | _ 1 7 | 8 _ 2 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 5 _ _ | 1 _ (8| 4 7 9 |
| _ _ _ | 9 4 _ | 5 2 8 |
| _ _ _ | 5 7 _ | 1 3 6 |
| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |

What I got at a brief over view.
The (8 is one I'm not sure about, but I think it might go thier.

[SoyLeche]

Originally Posted by Luke Wolf

| ~ ~ ~ | ~ ~ ~ | ~ ~ ~ |
| 4 1 6 | 2 5 9 | 3 8 7 |
| _ _ _ | _ 8</