dailysudoku.com

As often, various routes. After the xy-wing noted by Johan, I used a different skyscraper of 4's in c2 and c9 to remove the 4 in r9c7, and then it was clear sailing. (See the posted grids, esp that by ...

Hi cgordon,
My hint above leads to all '2' candidates in c5, being in box8: that will clear out the one you are interested in. Laughing

Don.

Lots of interesting observations based on the two grids shown (by storm_norm and Johan), which are the same. Shocked

Marty probably found that the solution fell out easily after the 2 in r7c8 was el ...

Sorry, I keep making notation errors: the pivot I used was r4c3. Embarassed

At the risk of making another such error, I will add a note for cgordon: the first xy-wing is 26-27-67 pivoted on r5c7. The th ...

For me, the two alternatives given by re'born are not one-step solutions. However, that was an interesting analysis of the DP by re'born and Johan. (Should we give this a UR Type number?) Anyway, my s ...

Thanks for all the feedback! Clearly people have varying feelings about certain things that affect how we proceed with suduko--and with life.
As for colouring, eh (Canadian spelling), I must do some ...

Having reached the following BUG+1 position that cgordon notes, using that x-wing on 6's and an only slightly different xy-wing, I still cannot understand a proof I read about a BUG having no solution ...

cgordon,
The Latin root of the word "obvious" is interesting in that it evokes the possibility of its opposite meaning! Indeed an archaic meaning is to stand in the way of something. ...

Underlining Marty's observation about multiple solution paths, here is Johan's grid after utilizing the x-wing Peter noted:
+-------------+---------+--------------+
| 8 7 2 | 1 6 3 | 4 9 ...

Sheryl,
Considering Marty's suggestion and your response, I think you don't have a handle on xy-wings yet. The wing he noted eliminates the 3 in r2c1. Maybe think of that 3's effect if it were true ...

Keith,
I hope Sheryl doesn't get a headache from your statements that are true if you ignore all the singles, but otherwise are mostly not true! But I think your point must be that her grid (which i ...

I find myself never using swordfish these days: other techniques seem to make them unnecessary. I do, however, spot xy-wings more easily than ever as a result of experience, I suppose. It turns out I ...

In a rush, I often do something wrong: There should have been a 1 in r3c8 as follows:
+-----------------+---------+-----------------+
| 1 24579 258 | 6 49 3 | 4789 24789 2789 |
| 278 24679 ...

Sweedy,
Consider the point at which I got stuck:

+-----------------+---------+-----------------+
| 1 24579 258 | 6 49 3 | 4789 24789 2789 |
| 278 24679 268 | 1 49 27 | 5 3 2789 |
...

Now that the "spoiler" is out there, I have to say that the positioning of the pair in c9 among an especially large number of alternative candidates was truly difficult for me to spot. (I fo ...

Tracy,
I was looking at sdq_pete's grid, just before my first post here.
Smile

Don D.

Sorry, "uses pincers at r6c9..." should read "uses pincers at r7c9...".
Embarassed

Don D.

Hi cgordon,
Using your grid: the xy-wing you just quoted (but haven't seen in detail yet) "pivoted on R9C7" uses pincers at r6c9, r9c3; this removes the 3 at r7c3. From there your grid solv ...

Tracy, I agree that...The fin can't be excluded in a finned fish.
However, isn't the 1 at r9c4 a fin for a "different" fish with the same corners in r67?
Confused

Don D.

Earl wrote:I used a finned X-wing on the 1's in R67, C49 TWICE to eliminate the 1's in R7C6 and R9C4. Is that legitimate?I think re-wording might help to legitimize: One could say that there is a finn ...