## Superior Sudoku 18

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### Superior Sudoku 18

I'm stuck as usual. But also want to see if there a Swordfish here for the twos:

R4C2 to R4C5
R7C1 to R7C6
R8C2 to R8C4

Is this right? And if so, does t his allow me to rid the 2s in R5C4 & R6C4?

(5)(7)(9) | (4)(2)(8) | (3)(1)(6)
(8)(4)(2) | (3)(16)(16) | (9)(7)(5)
(3)(1)(6) | (9)(7)(5) | (2)(8)(4)
(4)(26)(17) | (1267)(5)(3) | (167)(9)(8)
(26)(3)(8) | (1267)(9)(27) | (5)(4)(12)
(9)(5)(17) | (1267)(8)(4) | (167)(36)(123)
(26)(9)(3) | (8)(16)(27) | (4)(5)(17)
(1)(26)(5) | (27)(4)(9) | (8)(36)(37)
(7)(8)(4) | (5)(3)(16) | (16)(2)(9)

If so. The puzzle solves itself from this point.
SuDokuKid

Posts: 31
Joined: 02 November 2005

This is a pappocom puzzle so it is unlikely to contain a swordfish.

For a swordfish you need a number to appear in 3 columns and three corresponding Rows.

This number can only appear in 3 Rows, each of these Rows containing NO MORE than 3 cells with the number 2 (in your case) and the cells in these Rows all sharing 3 Columns (or visa versa).
You don't need to have the number 2 in all three Columns in each row, or the number 2 in all three Rows of each Column.

You have 3 Rows which contain the number 2 in two places in each Row, but if you look at the Columns the number 2 appears in C1, C2, C4, C5, & C6. So You don't have 3 specific Columns that the number 2 appears in, Hence not a Swordfish.

To solve this Puzzle you need to look again at the Number 2 for a X-Wing. Look down the Columns for two Columns that contain the number 2 in the same 2 Rows and then you can eliminate other 2's in these Rows, and the Puzzle should solve itself from there.

Hope this explains it and is of help
Crazy Girl

Posts: 189
Joined: 08 November 2005

Thanks. I still don't get the swordfish thing.

But on to an xwing.

Is the xwing:

The twos at: R4C2-R8C2 & R4C4-R8C4?

Is this right? And if so, does t his allow me to rid the 2s in R5C4 & R6C4?
SuDokuKid

Posts: 31
Joined: 02 November 2005

SuDokuKid wrote:I still don't get the swordfish thing.

The swordfish has to be in 3 rows and 3 columns – yours is in 3 rows (4,7,8) and 5 columns (1,2,4,5,6)

Is the xwing: The twos at: R4C2-R8C2 & R4C4-R8C4?

... And if so, does t his allow me to rid the 2s in R5C4 & R6C4?

Yes and yes.
emm

Posts: 987
Joined: 02 July 2005

SuDokuKid

Once you've carried out your eliminations a further xwing is exposed in the 2's, leading to an elimination and a placement.
MCC

Posts: 1275
Joined: 08 June 2005

What you have found is a valid X-Wing on 2, but the one I found was
R5C1, R7C1, R5C6, R7C6. which allows you to eliminate the 2's in R5C4 & R5C9. Leading to a Naked Single.

There are different ways people tackle a puzzle, and if your way works stick with it.
Crazy Girl

Posts: 189
Joined: 08 November 2005