The New Sudoku Players' Forum

[bjschnei]

I guess there is supposed to be a swordfish in this puzzle somewhere..but I don't see it. Can someone explain? This puzzle is from http://www.simes.clara.co.uk/programs/sudokutechnique6.htm swordfish2 puzzle....For some reason the sadman software doesn't seem to ever give swordfish as a hint...always seems to be coloring...

here is where i am..

[Ruud]

Hi,

There is a swordfish for digit 5 in this position:



(the blue cells form the swordfish, the red cells are the victims)

Ruud.

[bjschnei]

Thanks Ruud...can you explain why/how the swordfish is working here..i still don't see how it works.

[Ruud]

Ok,

the candidates for digit 5 in rows {3,5,7} occupy only 3 columns {3,4,7}

so, when those 3 rows each have a digit 5, all those 3 columns have a digit 5 placed somewhere on those 3 rows.

Other candidates for digit 5 in those columns can be eliminated.

--

For more examples, check the explanations here:

http://www.simes.clara.co.uk/programs/sudokutechnique6.htm

Ruud.

[bjschnei]

what is the difference between row 4 and 5?

[bjschnei]

nevermind...row 4 has other candidtates for a 5 not in a common column