Kungfuzed said:
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.