dailysudoku.com

[sdq_pete]

I solved it after two or three sessions. I was wondering whether others reached the same situation and found the same solution - what unlocked it for me was a sort of "skew" XY-wing. The situation was as follows:

[Marty R.]

I haven't done the puzzle yet, but what you did I know as "XY-Wing Chain", where if you have a chain of a pair with an odd number of cells, the start and end cells of the chain work as an XY-Wing.

[Golfgal]

How did you get the 6 in row 4, column 2?

[Mesmin]

[Marty R.]

[jerry2007]

Can you explain to me how you determined that R1C1 or R4C3 must be a 9? I just don't see it... Thank you

[Marty R.]

[Mesmin]

[Mesmin]

Beaten to the reply while I was typing. Serves me right for surfing the forums while at work.

[dulaby]

Here are the steps I used for this one:1-) there is an xy-wing on boxes 1 and 7 so that 7 is out of r3c1. 2-) after that an x-wing appears on columns 1 and 8(on 7) .Then you can choose several ways to complete it(assuming I am right...).

[jerry2007]

Thank you for the explanation.. It is a new technique I have learned today

[Emily]

I solved this puzzle, but I'm not sure I did it correctly -- this was my first attempt trying to use any kind of Wing technique -- and would appreciate if someone would tell me. I apologize in advance for my lack of use of the more technically appropriate terms.

I reached the point noted above with the exception of the 6 in r4c2.

I used the 9s in r1c1 - r1c6 - r4c6 - r6c5 to eliminate the possibility of a 9 in r6c1.

That left me with the (1,7) pair in r6c1 and r6c2. That allowed me to fill in the 6 in r4c2, leaving me with (2,9) in r4c3 and r6c3 and (3,6,7) in the remainder of column 3, allowing me to fill in the 7 inn r3c3, and the rest of the puzzle came easily.

So my question, I suppose is, did I correctly eliminate the 9 in position r6c1 which allowed me to complete the puzzle, or did I just back into it?

[George Woods]

I sometimes find that the "formal" solutions seem to be more suitable for computer programmes, rather than the loose creative thoughts that happen when I am on song. I personally hate to pencil in anything more than doublets

That being so - given the crunch point earlier (but without the 6 in r4c2) I was looking at col3 and observing that a seven in r3c3 would give the 2 and 9 in box 4 immediately - this happens if r4c6 is 9

BUT if r4c6 is 8 then r4c9 is 7, and if r4c6 is 9 then as described above r4c3 is 2 and so row 4 solves with r4c9 as 7

so r4c9 is 7 irrespective of whether r4c6 is 8 or 9.

so from here the solution falls out!

Incidentally Welcome back Forum after the long break!

[sdq_pete]

[sdq_pete]

[David]

Since we are discussing roads to Rome and Vienna.............. you can also solve the puzzle using strong links / colouring. So taking Marty's posting above, and focusing on the 9's; r4c6-r1c6-r1c1-r3c3 allows the elimination of 9 from r4c3 and hence forces the 9's in box 4 into row 6.

[Jeff]

I am stumped on the May 1 puzzle. Here is what I have. The Hint says that a 6 goes in Row 4 Col 2. I cannot figure how this can be. Mesmin on earlier post indicated that x-wing, xy wing, and naked pair would do it. I can't figure out where the x-wing is and of course I also can't find the xy and naked pair.

[/code]
59/2/8/35/1/39/7/6/4
6/3/4/58/2/7/9/58/1
179/157/79/6/89/4/358/38/2
3/67/2679/1/5/89/28/4/78
8/4/5/7/3/2/1/9/6
179/17/279/4/89/6/238/378/5
2/678/367/9/4/5/68/1/378
4/568/36/38/7/1/568/2/9
57/9/1/2/6/38/4/578/378

Could someone tell me how to write these number in the nice neat box as was done at the beginning of the discussion on the May 1 puzzle. I tried to find some instructions, but couldn't find any.

Many thanks.

[Marty R.]

Jeff,

There are two good ways to post a properly aligned grid.

If you are doing a puzzle (regardless of puzzle source) online on this site, all you have to do is click the "Ascii" button to the right of the grid. Then follow the instructions in the pop-up window to copy and paste the grid into the message box.

Otherwise, type the grid into Notepad, which uses a fixed xx font, or into a word processing program, and choose a font that uses a fixed xx, such as Courier New. Proofread the grid before posting. Select (highlight) the grid and copy it (Ctrl+C). In the forum message box, click "Code", then paste (Ctrl+V) the grid to the right of the Code tag. Click "Code" again which inserts the tag at the end of the grid.

A properly aligned grid makes it easier for people to analyze your position and may well get you a quicker response.

This is an example of a grid which was first typed into Notepad. It takes less time than it looks like, as once you establish the maximum number of spaces per cell, you get into a rhythm and it takes less than five minutes.

[Jeff]

I am stumped on the May 1 puzzle. I finally figured out how to put the numbers into a nice grid, thanks to some suggestions from the very knowledgeable group.

The hint states that a 6 should go in R4C2. In an earlier message "Mesmin" said that this comes about by "X-wing, XY wing, and then a naked pair". Could some one lead me through this. I don't see an X-wing anywhere, so I can't get to the XY or Naked pair.

Many thanks.

[Mesmin]

Jeff,

From where you are you don't need the X-Wing. Just the XY and then the naked pair. Box1 is where you should be looking. If you need a more precise hint, let me know.

Perhaps I went a round about way with the X-Wing, and it isn't really required.