dailysudoku.com

[Rocky Mozell]

249 XY-wing with pivot r7c1. How is this the first post?

[eddieg]

I never post, but always work the VH puzzles. Love this site.

[williamholiday]

Hi,
New member here. Been doing the puzzles @ DS for a while and now I want to talk a little strategy, if that's OK?

Today's VH(4/1). After getting about half way and facing a combination that I couldn't "compute" but that I hoped would "trigger" the remainder, I took a screenshot, and ran the first option. It didn't work but after reconstructing the board, the second resulted in a solve. This is the second time I've solved the VH level, though sometimes an H will stump me, and both times I've had to go to what is essentially, trial and error.

Is "hit or miss" a typical technique for anybody else?

-william.

[Marty R.]

This puzzle seemed to have a busier grid and required a lot more basics work than most. I also used the 492 XY-Wing.

William, welcome to the forum.

[williamholiday]

Hi Marty,

Thanks for the reply.

Most of the time there's a eureka moment. A day or so ago, on a Hard puzzle, the cell(s) that tripped the rest of the puzzle was an either-or across two of the 9 grids rather than within one, if you know what I mean. It was fun to work up to that point and then spot that.

On today's puzzle I never found the place where the exception proved the puzzle. I got to a point where one cell was a one and another was a three and I solved for both by entering numbers rather than by looking and figuring. I just wondered if others solved the VH class puzzles this way sometimes. On both of the VH ones that I finished I used this kludge, I had to enter numbers on the sheet, I couldn't do the logic without writing.

all the best,
-william.

[keith]

William,

I think you mean "pencil marks", which is when you note the possible candidates in unsolved cells.

I always use pencil marks on this site's Very Hard puzzles. As a personal challenge, I do not use them on Hard puzzles.

People use all kinds of rules to make easy puzzles more challenging. For example, you have to solve all the cells in a block before moving on to another block.

By the way, you will see people use a number of techniques, but this site's Very Hard puzzles can be solved with only three "advanced" patterns: X-wing, XY-wing, and XYZ-wing. You can look up those terms on Google, or go to sudopedia.org.

Welcome to the forum! The crowd here is knowledgeable, helpful and courteous.

Best wishes,

Keith

[williamholiday]

Ladies and Gentlemen, Keith,

I thought I had taken a short cut and I'm now I'm sure(but I was soooo proud of finishing, I had to find out 8-)

I'm going to do a little research, thanks for the pointer. I particularly like the quality and play at this site and of course, the community is stellar!

-william.

[keith]

William,

Remember that this site is a wonderful place for tutorials. Don't wait for the new puzzles. For each previous Very Hard puzzle, there is a discussion on how to solve it*. And, there is almost never one solution path.

So, please explore the discussions of past puzzles.

Keith

* Except, a few years ago, some discussions for a period of a year or so were lost in a system crash.

[Ema Nymton]

.

Being a visual learner that I am, after the basics I found myself with this puzzle:

[Marty R.]

[williamholiday]

Thanks again Kieth and Ema, your graphic is exactly where I was when I ran out of techniques and turned to blunt force solving. I took a look at the sudopedia and expect to integrate the xyz-wing as time goes by. That combination of 3 numbers crops up a lot and I didn't know that it provided eliminations. That was the core question I initially posed "What do folks do when they run out of tools?" And now I know a new one.

I took a look at the first post again and it make sense after this little discussion.

all the best