Everything about Sudoku that doesn't fit in one of the other sections
re'born wrote:Perhaps this transported wxyz-wing will fare better. An assist goes to JPF for more or less finding this puzzle

Sorry, but in this case I'd say the XY chain [r2c4]-5-[r1c6]-1-[r4c6]-5-[r5c5] (r3c5 and r6c4<>7) is definitely easier. It considers fewer cells and only bivalue cells. If I recall correctly someone has actually given this particular pattern (two 'ab' bivalue cells connected by two 'ac' bivalue cells) a name because it's so easy to find.

RW
RW
2010 Supporter

Posts: 1000
Joined: 16 March 2006

I don't know whether to be happy I've gotten so good at finding xyz-wings, or sad that I've gotten so bad at spotting xy-chains. Here is my next attempt:
Code: Select all
`. 9 4|7 . 5|. . .5 . 8|. 6 .|. . .. . .|. 8 .|4 . .-----+-----+-----. . .|. . .|. . 6. . 6|8 9 .|2 3 .. 1 .|3 7 .|. . 5-----+-----+-----. . .|. 2 .|. 9 8. . .|5 . .|. . 31 . .|. . .|. 7 .`

After basics we get to
Code: Select all
`.------------------.------------------.------------------.| 23    9     4    | 7     13    5    | 8     6     12   || 5     27    8    | 1249  6     1249 | 3     12    79   || 236   2367  1    | 29    8     239  | 4     5     79   |:------------------+------------------+------------------:| 3489  348   39   | 124   5     124  | 7     148   6    || 7     5     6    | 8     9     14   | 2     3     14   || 48    1     2    | 3     7     6    | 9     48    5    |:------------------+------------------+------------------:| 346   346   357  | 16A   2     137  | 156B  9     8    || 2689  268   79   | 5     14    1789 | 16    24    3    || 1     2368  359  | 69    34    389  | 56C   7     24   |'------------------'------------------'------------------'`

where the xyz-wing eliminates nothing. But we can transport C to A via:
[r7c4 = 6 = r9c4 - 6 - r9c7]
and hence we can eliminate everything that sees A and B, i.e., r7c12<>6, reducing the puzzle to basics.
re'born

Posts: 551
Joined: 31 May 2007

Previous