X-Treme Dec 23

[emm]

Just for the record I am actually having a little bit of trouble with X-Treme Dec 23 - but I'm sure I would be able to solve it if it wasn't Christmas and I had more time.

I'll have another go when all the eating and drinking is over. In the meantime thanks Ruud for lots of fun on your forum.

Happy Christmas from Downunder!

[emm]

It has been fairly torrid getting to this point - I have used uniqueness and a lot of contradiction chains -

Code: Select all

 
 *--------------------------------------------------*
 | 2    14   134  | 7    9    5    | 8    34   6    |
 | 7    8    34   | 6    34   1    | 9    5    2    |
 | 9    5    6    | 38   2    48   | 34   7    1    |
 |----------------+----------------+----------------|
 | 36   13   15   | 9    56   28   | 7    28   4    |
 | 48   2    7    | 48   1    3    | 5    6    9    |
 | 46   9    58   | 248  56   7    | 1    28   3    |
 |----------------+----------------+----------------|
 | 5    6    9    | 23   8    24   | 34   1    7    |
 | 1    7    2    | 5    34   9    | 6    34   8    |
 | 38   34   48   | 1    7    6    | 2    9    5    |
 *--------------------------------------------------*

Almost a BUG but not quite. Any ideas?

[sudokuEd]

An ALS move unlocks the puzzle emm

ALS(A=[r9c1,r4c6]B=[r356c4], X = 2, Z= 3) -> r3c7<>3

But I can't get as far as emm has. Any more ideas?

Code: Select all

.---------------.---------------.---------------.
| 234  1234 134 | 7    9    5   | 8    34   6   |
| 7    8    34  | 6    34   1   | 9    5    2   |
| 9    5    6   | 38   2    48  | 34   7    1   |
:---------------+---------------+---------------:
| 36   13   135 | 29   56   289 | 7    28   4   |
| 248  24   7   | 248  1    3   | 5    6    9   |
| 46   249  4589| 248  56   7   | 1    28   3   |
:---------------+---------------+---------------:
| 5    6    29  | 239  8    24  | 34   1    7   |
| 1    7    234 | 5    34   249 | 6    349  8   |
| 348  349  3489| 1    7    6   | 2    349  5   |
'---------------'---------------'---------------'

[Ruud]

you could start with the X-Wing for digit 4 in r37c67...

then there is this nice loop:

[r9c1]-8-[r4c6]=8=[r3c6]=4=[r3c7]=3=[r9c1] => r9c1<>8

several singles bring you to this point:

Code: Select all

.------------.------------.------------.
| 2  1-34 134| 7   9   5  | 8  *34  6  |
| 7   8   34 | 6   34  1  | 9   5   2  |
| 9   5   6  | 38  2   48 |*34  7   1  |
:------------+------------+------------:
| 36  13  135| 9   56  28 | 7   28  4  |
| 8   2   7  | 4   1   3  | 5   6   9  |
| 46  9   45 | 28  56  7  | 1   28  3  |
:------------+------------+------------:
| 5   6   9  | 23  8   24 | 34  1   7  |
| 1   7   2  | 5   34  9  | 6   34  8  |
|*34 *34  8  | 1   7   6  | 2   9   5  |
'------------'------------'------------'

A remote pair using the diagonal causes a single 1 in r1c2.

That finally cracks it.

Ruud

[emm]

Very nice moves. Looks so easy when someone shows you how. Thanks!