The New Sudoku Players' Forum

[LuCiPh33R]

I'm just started doing them, and they're quite enjoyable. I want to learn the X-wings and swordfish techniques but I don't follow the nomenclature you folks are using!

Using as an example

The value 3 in Box [1,3] must lie in Row 2.
The value 3 in Box [3,2] must lie in Column 6.
The value 7 in Column 5 must lie in Box [2,2].

Is it [column, row] or the other way round. I don't quite follow.

Cheers

[Animator]

Almost everyone uses row, column...


But for the boxes there are two possibilities. For example, to identify the middle box you could say: Box 5 and Box [2, 2]. I usually use the one decimal notiation, but suit yourself... :)

[lunababy_moonchild]

I'm practicing x-wings and working my way up to swordfish myself, so I'll leave the explaining of that to someone more proficient.

As for nomenclature, basic terms are here : Basic Terms

Hope that helps!

Luna

[Animator]

For the record: the only time you might need an X-wing is on the very hard puzzle. You would need a swordfish when you go on beyond very hard... but the program does not generate those puzzles... (unfortunally I may add)

Here is a really basic explenation of an X-Wing (the same goes for rows too):

* First, look for a column in which a certain number has only two possible candidate-cells.
* Second, look for another column which has two possible candidate-cells for the same number aswell.
* You have an X-wing if, and only if: the first candidate of column A is on the same row as the first candidate of column B and the second candidate of column A is on the same row as the second candidate of column B

* When you found this you can remove the number as candidate from all other cells on the two rows (except in column A and column B).


Ofcourse explaining it only with words is hard, so feel free to look at the other posts asking help with a 'Very Hard' puzzle, or the ones that explains X-wings