The New Sudoku Players' Forum

[georgers]

Would be most grateful if someone could give me a clue --- I guess I am missing something obvious. I've been looking at it for a week and it doesn't get any better!

x4x x81 xxx
2xx 4xx 65x
xx3 xx5 xx4

91x 5xx 3xx
xx2 1xx 9xx
3x4 xxx 517

6xx 85x 4xx
x37 xx9 xx5
xxx 31x x6x

Have found X-wing's in 1's and 3's and a various pairs and triples but so far can't see a next step.

Be most grateful if anyone can be bothered.....

George
(georgers1@gmail.com)

[simes]

Naked pair in block 4, then row 5, then column 1. Then a few block/column/row interactions and it's done.

Simes

[georgers]

Err ... thank you. I have 2 naked pairs in Block 4 ( 5,7 and 6,8). I also have a naked pair in Column 1 (5,7 again). There's a naked pair in Block 3 also (1,8). And a naked pair in Row 3 (1,8 again).

But it's where I go from there that I haven't found --- must be missing something totally obvious or I've gone wrong somewhere. Could you spell out the next step?

Thanks very much in advance.

George
(georgers1@gmail.com)

[simes]

okley dokley...

Sorry... looked deeper, those pairs don't help much!

block 8 column 6, look at digit 7 and make an elimination in r2c6

simes

[georgers]

Thanks very much ---- and it only took you 10 minutes, gnash, gnash!

All best!

[Doyle]

That particular type of clue (that simes supplied), though elementary, is easy to overlook: In a given box, a particular value can be in one of only two cells, and those two cells are in a single row, or a single column, therefore excluding that value from all other cells in that row, or column, in the two other boxes as well. This situation is so common, so useful, but so (relatively) opaque, that I've taken to entering a distinct pencil mark for it. Does it have a name? If not, it should.

[george-no1]

Yes, you're referring to restricted candidates.