dailysudoku.com

[Xantara]

Hi people,

I have completed SOME of the "very hard" puzzles. But I don't always get them all.
June 16 has me stumped.

I read about the "naked triple" in col. 7.
Would that be the 359, 359, 59 triple????? How do I use it to help?
I have the rest of that column solved except for those three squares.

Anyroad ------
Here's what my puzzle looks like so far:

5 x x x 2 1 7 x x
x x 3 5 x x 1 x x
7 x 1 x 3 9 2 x 5

1 7 2 x 8 x x x x
x 4 x 1 x 2 x 8 7
x x x x 4 x 6 2 1

9 x x 2 x x 8 x x
x x x x x 8 4 x x
x x 7 3 1 x x x 2

Suggestions welcome.
Thanks.

Xantara

[Marty R.]

[David Bryant]

Hi, Xantara!

The triplet you mentioned ({3, 5, 9} in column 7) is of little use at this stage.

The key to making further progress from the position you posted lies in the bottom right 3x3 box.

-- Because of the {1, 7} in column 7, column 9, and row 9, you can identify a hidden pair {1, 7} lying in r7c8 & r8c8.

-- It is evident that the "9" in row 8 must lie in the bottom center 3x3 box; that is, the "9" in row 8 lies at r8c4 or r8c5.

-- Since there's a "5" at r3c9 it's clear that the pair {5, 9} must lie in r9c7 & r9c8. That leaves the pair {3, 6} in r7c9 & r8c9.

-- Now there's only one square left in the top right 3x3 box that can possibly contain a "3". So you can set r1c8 = 3 and r3c8 = 6, and be merrily on your way. dcb

[Xantara]

Those hidden pairs are so hard to catch! I appreciate entirely your clear explanation. Thank you kindly.

"By the Shadow of Death, but he's a lightning pilot!" - Mark Twain, Life on the Mississippi, ch. 7