dailysudoku.com

keith · Posted: Sun Jul 15, 2007 6:22 pm Post subject: Very hard plus?

I found this one, surprisingly, in a advertising flyer. Pretty good!

(And yes, I see it is not symmetric.)

Keith

Asellus · Posted: Sun Jul 15, 2007 8:12 pm Post subject:

Several possible moves in this one. But, I found one step that solves the whole thing. Only hint: it involves strong links and bivalues.

keith · Posted: Sun Jul 15, 2007 8:24 pm Post subject:

I had a couple of UR's, don't know if they were needed. And, as I recall, an XY-wing.

Then I got to a point where there are no UR's, no X-wings or other fish, no XY- or XYZ-wings, no coloring or skyscrapers that that I could see.

What's left? Our new friend, the W-wing!.

Keith

Asellus · Posted: Sun Jul 15, 2007 8:38 pm Post subject:

Yes, a W-Wing. The one I found is "robust," i.e. both X and Y are strong links... though this makes no difference to the solution. It was also available after basic methods and solves the entire puzzle.

I found an XY-Wing and a Finned X-Wing (maybe some other stuff, don't recall) that helped, but didn't solve it.