The New Sudoku Players' Forum

[Guest]

I'm looking for help on a particularly tricky puzzle. Here's where I am so far:

6 4 7 * 5 39 1 * 389 38 2
5 1 38 * 389 2 3789 * 4 6 3789
9 28 238 * 368 4 3678 * 378 1 5

7 3 689 * 69 5 2 * 1 4 68
1 289 2689 * 7 39 4 * 238 5 368
4 25 256 * 1 8 36 * 237 9 367

2 7 59 * 4 6 3589 * 389 38 1
8 59 1 * 39 7 359 * 6 2 4
3 6 4 * 2 1 89 * 5 7 89

[Guest]

Alas, I'm not much help, but I did paste the puzzle into
Simple Sudoku. So, as a minor contribution, here is the puzzle in
the Simple Sudoku format:

Code: Select all

 *-----------*
 |647|5.1|..2|
 |51.|.2.|46.|
 |9..|.4.|.15|
 |---+---+---|
 |73.|.52|14.|
 |1..|7.4|.5.|
 |4..|18.|.9.|
 |---+---+---|
 |27.|46.|..1|
 |8.1|.7.|624|
 |364|21.|57.|
 *-----------*

 *-----------------------------------------------------------*
 | 6     4     7     | 5     39    1     | 389   38    2     |
 | 5     1     38    | 389   2     3789  | 4     6     3789  |
 | 9     28    238   | 368   4     3678  | 378   1     5     |
 |-------------------+-------------------+-------------------|
 | 7     3     689   | 69    5     2     | 1     4     68    |
 | 1     289   2689  | 7     39    4     | 238   5     368   |
 | 4     25    256   | 1     8     36    | 237   9     367   |
 |-------------------+-------------------+-------------------|
 | 2     7     59    | 4     6     3589  | 389   38    1     |
 | 8     59    1     | 39    7     359   | 6     2     4     |
 | 3     6     4     | 2     1     89    | 5     7     89    |
 *-----------------------------------------------------------*


[Shazbot]

Thanks Guest - it's always nice to see puzzles in this format.

From this grid, see where 3s can go in box 9, and 8s in row 1 or column 6 (locked candidates). Once you've excluded all other candidates based on those, the next step is colouring. Read up on it
here

[Hud]

Shazbot, thanks for the tip to use colouring. I had never done it but had read the same tutorial you referenced before I really knew what it meant. I did find two different xy wings before using it, but they didn't lead to the solution which colouring did. It almost felt like cheating when it worked. Whoopee

[Shazbot]

After colouring, an WY wing was required according to Simple Sudoku - I still can't pick those up - from what I understand, it's a very simple kind of forcing chain (don't know enough about those yet either) - they're the next two lessons on my list.

[Hud]

In the candidate grid above,

69 at R4C4 = xy
39 at R8c4 = xz
36 at R6C6 = yz

eliminate z(3) from R7C6 and R8C6

The second emerged later up near the top but was a little different in that the z was eliminated in the xy, xz row. I can't recall exactly what it was though. I find them fun to uncover and consider them easier than colouring or swordfish (which I haven't learned to do yet [but will]).

[Shazbot]

I find them fun to uncover and consider them easier than colouring or swordfish (which I haven't learned to do yet [but will]).

wow - I love finding swordfish, and find it nearly as easy as XWings now (easier than hidden pairs, triples and quads!), and I'm getting the hang of colouring too. XY Wings are still something of a mystery!