Seems as valid as any technique. Plus, I could not unsee it if I wanted to....so what can you do...lol

There are quite a few puzzles I finish and then go over the solution and see there was a X wing or there was an XY wing, and I am thinking ORLY.... I didn't encounter any.

The solutions must be hard to program, because they don't know what order exactly the solver is going to find locked pairs or other things that are going to solve a few numbers, thus never requiring the X, or XY wing etc to even come into play.

Watching some of the Simon vids is helpful for ways to pick off stuff early and I think some of those steps can save you some tedious X or XY searches later.

PS. I would like to find more of those thermo games. The few i found were fun.

[rant]
One issue I have with uniqueness is best illustrated in a BUG+1 situation. The rule of thumb is to use the +1, otherwise the resulting grid has two solutions (by flipping the bivalue cells). I contend that those two solutions are no less valid than the "accepted" one. That is, the puzzle is already "bad" because it allows three solutions, obtained by choosing any of the values of the +1 cell.

Obviously, that situation is an endgame one. In the middle game, it may not be that all three values of the cell in question will lead to a solution, and if there is a unique solution, it has to be the one that removes the deadly pattern. In that case, there must be a logical way of eliminating it, without meta-gaming.

The way I see it, there are three types of solvers:
1. Speed solvers - whatever you have to do, go for it.
2. People like me who derive their pleasure from the logical solve - avoid it.
3. People who are just passing time or neophytes - whatever you want.

And while I'm on the topic of sudoku philosophy (if anyone is still here), I have strong opinions on techniques like chains and colouring. These are nothing more than tarted up trial-and-error, guess-and-test, bifurcation. I hate these with a passion. The only logic involved with these is when you realize it doesn't work or you have finished the puzzle. Again, if you are solver type 1 or 3, these are fine and necessary. For type 2, they are anti-thematic.

[/rant]

Sorry for using your post as a springboard, AK, but I have unusually strong thoughts about these. Covid and nuclear threats don't bother me, but sudoku ...

On a more positive note, I have backed CTC's kickstarter for three copies. One is for me, one I will give to a coworker, and one I plan to have as a prize for a POG game at some point, probably late next year (when the book should be out).

No problem using my post as a prompt to share thoughts, Eric.

To me Sudoku is me against the puzzle thing that I do once a day for fun. I won't brute force solve because that would be no fun (for me).

I have no interest in how strict or lax other people are with solving techniques. I am not playing against them in any way, so I can't imagine why I would care.

True enough. I get carried away sometimes.

If I run a sudoku -themed game next year, who would be interested and should it be about solving sudoku (of assorted difficulties and variants)? I wouldn't want it to be speed-solving. Would some kind of sheep game or guesstimania be better?

Not really on the bold. We really are not different. if you think about it the parameters/code you set for yourself is really about it not being fun and/or not a proper challenge for you if you did not have those parameters.

There is nothing wrong or too carried away about that..

I don't think I would be interested in any form of Sudoku competition. The reason I like it is because it is not a competition. Sort of the opposite of Triplechain. TC would be no fun if was not competitive.

Others probably would though.

Simon made a logical leap that escaped me in this one.



When he does the bit at around the 24:00 mark it's rather brilliant, but I'm wondering if his logic is faulty and that he might have lucked into placing correct digits into the 20 cage on the bottom right corner of the board. It seems like he's done a variation on Phistomefel's theorem, but I'm still not sold on his reasoning. As I see it, a 5 is necessary in the 20 cage, but why does it have to be a 569? Why not 578?

He had proven that the large orange region contains the digits 1-9 plus the exact same digits that are in the small orange region. And we know there are 2 9s in it. So subtracting out that set of 1-9, there is still a 9 left. So it must go in the 20 cage.

So it truly is a variation on Phistomefel. Simon's a freaking savant.

Not Sudoku related, but might be of interest to people here.

It's an interesting series of videos breaking down the solving of the Zodiac Killer's messages, which were finally deciphered earlier this month.

Bump. Funny seeing the two guys clearly fanboying out.

But seriously, just WTF...? It takes me longer to understand the rules!

That was absolutely insane lol

omg, that girl is incredible.

I have created an Arrow Sudoku, and I am hoping to find testers here. It should be approachable, as they say, but I'm not sure if it is too easy or too hard. At times, it seemed like both, so maybe it's good. Please try it, and let me know what you think.

For those who do not know, an Arrow Sudoku has circles in the grid with arrows coming out of them. The sum of the numbers on an arrow is the number that goes into the attached circle. Otherwise, normal sudoku rules apply.

A clarification about my puzzle is that there are some squares which are on more than one arrow, and it is hard to show how the intersecting arrows are supposed to flow.

In the top right 3x3 block, the arrow that starts in row 2 column 9 goes left one square then turns up. The other arrow turns down at the intersection.

In the bottom left 3x3 block, the arrow that starts in row 8 column 1 goes right one square then turns down. The other arrow turns up at the intersection. I'm sorry if it is confusing

Here is the link to the f-puzzles site so you can solve it.

https://f-puzzles.com/?id=yzx7o35j

I'll try today or Tuesday and will PM you a screenshot if I get it.

Thanks!

Hid time cause I had to restart twice to find the path to the end. Tried different patterns to focus on until I realized some hidden patterns

Method to solve in the spoilers. Don't click if you don't want to know what happens. Just my thoughts after spending probably 90+ minutes with restarts/breaks.



Note: I got stuck resetting back to picture 1, only getting to picture 3 when I actually completing it.

I wonder if rotating the grid by 90° would have helped me find the breaking point.

Eric

When I saw the spoiler I could not resist.

Here is where I went wrong



Neat one though. I would do one again.

Thanks for trying this, guys. I'll comment later.

do you have any more

Some commentary and hints

I only have one, which I created a couple of years ago. I'll see about putting into f-puzzles. I'm trying to work on more arrow puzzles at the moment.

I don't care for mixing variants, so it's not as easy as for some of the beautiful looking puzzles that one may see on CtC or the discord (which I recently joined, user EPH).

Have you posted this puzzle on there yet?

Might want to e-mail CtC with that puzzle see if it gets solved or even gets put into their new Arrow Sudoku app that's upcoming, you never know! They may be looking for more arrow sudokus.