The New Sudoku Players' Forum

[eddieb]

Hi, Newbie to this forum. I am 75 yrs of age and have been doing Sudoku (Basic - medium ) for over 20 years. Recently I came across Hudoku which is a Sudoku software programme for Linux, which I duly installed. Within a matter of days I went from basic/medium level to extreme mainly because I was able to use candidates ( pencil marks , please excuse my lack of experience with the terminology ) which I had never used before. My completion rate is quite dismal, although I should point out that this is not of great concern because I do Sudoku for entertainment and to keep my brain active. Now to my question, can someone tell me if there is a trick to selecting which numbers to use when I have come to a dead stop after searching for hidden numers that go in single/double and triple blank squares? I then look for four blank squares and whilst I understand the principle of three numbers in three squares I rarely get the correct numbers. I have taken the following from a game and can see at least two different answers.

4,7,8/ 2,4,7/ 2,7/ 2,7,8. One solution appears to be the number 2 and the other is the number 8.
I don't use the facility to have all the candidates filled in automatically, I appear to have unknowingly used the Snyder method, although I had never heard of it till a few days ago.
I hope I have made myself clear, at my age that is sometimes elusive.
Any help would be gratefully received.

Eddie.

[dobrichev]

Hi Robby Bootie,
I found your question closely related to this post and this was the answer I got using your brother from the link.

Now to my question, can someone tell me if there is a trick to selecting which numbers to use when I have come to a dead stop after searching for hidden numers that go in single/double and triple blank squares?

Quote from: biggray on February 10, 2011, 11:21:52 AM 1. to select the 5 numbers that appear at the end of a "triple blank" square:

Click on the arrow on the lower left of the screen

Click on "start"

Click on 1 (previous to first "triple blank" square)

After that, "next" (to the previous "triple blank" square)

Click on 2

After that, "next"

[eddieb]

Hi Robby Bootie,
I found your question closely related to this post and this was the answer I got using your brother from the link.

Now to my question, can someone tell me if there is a trick to selecting which numbers to use when I have come to a dead stop after searching for hidden numers that go in single/double and triple blank squares?

Quote from: biggray on February 10, 2011, 11:21:52 AM 1. to select the 5 numbers that appear at the end of a "triple blank" square:

Click on the arrow on the lower left of the screen

Click on "start"

Click on 1 (previous to first "triple blank" square)

After that, "next" (to the previous "triple blank" square)

Click on 2

After that, "next"

Thank you for your reply. However when I click the post that you indicate it appears to be something totally unrelated to my question?

[SteveG48]

Hi, Newbie to this forum.

Hello, Eddie. Welcome aboard.

Recently I came across Hudoku which is a Sudoku software programme for Linux, which I duly installed.

Congratulations on an excellent find. Hodoku is an excellent program for learning, for just working puzzles, and for doing more advanced things like constructing chains.

Within a matter of days I went from basic/medium level to extreme mainly because I was able to use candidates ( pencil marks , please excuse my lack of experience with the terminology ) which I had never used before. My completion rate is quite dismal, although I should point out that this is not of great concern because I do Sudoku for entertainment and to keep my brain active.

Understood, but let me suggest that working extreme puzzles isn't a good way to increase your skills. My suggestion is to work each level until you can consistently solve the puzzles that Hodoku generates at that level. If you get stuck, look at the logical solution that Hodoku presents and make sure that you understand it. There are always other ways to solve the puzzle, but you should understand the methods that Hodoku uses at each level.

Now to my question, can someone tell me if there is a trick to selecting which numbers to use when I have come to a dead stop after searching for hidden numers that go in single/double and triple blank squares?

If I understand your question, there is no trick. I just look at each sector (big box, line, or column) in turn. I look for doubles, triples, and higher sets in turn. I don't care which candidates are in those sets of cells. I just care that whichever candidates are there are the same. If I find a naked set, then I can eliminate whatever candidates make up that set from the other cells in that sector. I seldom look for hidden sets, because I find it easier to find even large naked sets than it is to find small hidden sets, but that's just me. Keep in mind that in any sector, if there is a hidden set in one set of cells, then there is a complimentary naked set in the other unassigned cells in that sector.

4,7,8/ 2,4,7/ 2,7/ 2,7,8. One solution appears to be the number 2 and the other is the number 8.

Now you've lost me. You have a set of four cells with just four candidates. That's good, because it tells you that each of those four candidates is correct in one of those cells, but it doesn't tell you which one goes in which cell. What it does do is allow you to eliminate those four candidates in every other cell in the same sector, since all of those candidates will be used in one of those four cells.

I don't use the facility to have all the candidates filled in automatically,

That in my opinion is a mistake. Automatic tracking of candidates is the great advantage of computerized Sudoku play versus pencil and paper. It's great for learning because it eliminates drudgery and many errors. Turning it off once in awhile, or just going to pencil and paper, is fun, but to sharpen your skills, turn it on.

I appear to have unknowingly used the Snyder method, although I had never heard of it till a few days ago.

Can't say that I've ever heard of it myself.

[eddieb]

SteveG48, thank you for your reply although to be honest it was of little help. I am surprised you haven't heard of Thomas Snyder, he's one of the top puzzle men in the World. His method is he only puts a candidate in a box 3x3 if it will only go in two places.
I am doing ( trying ) the extreme because I found the other levels below it quite easy. I have shown the four sets of candidates which according to instructions I should be able to pick three numbers which will allow me to find one number that stands out, my question is how do I know which set of three numbers is correct. I have indicated that to me there is two answers which cannot be correct.
Again thanks for your reply.

[tarek]

Snyder is a World Sudoku champion who used to be an active member of this forum using the name "motris"

[SpAce]

Hi eddieb,

Now to my question, can someone tell me if there is a trick to selecting which numbers to use when I have come to a dead stop after searching for hidden numers that go in single/double and triple blank squares? I then look for four blank squares and whilst I understand the principle of three numbers in three squares I rarely get the correct numbers. I have taken the following from a game and can see at least two different answers.

4,7,8/ 2,4,7/ 2,7/ 2,7,8. One solution appears to be the number 2 and the other is the number 8.
...
I have shown the four sets of candidates which according to instructions I should be able to pick three numbers which will allow me to find one number that stands out, my question is how do I know which set of three numbers is correct. I have indicated that to me there is two answers which cannot be correct.

Problem is, I don't think anyone understands your question. If you want better answers, you should probably provide a concrete example from a real puzzle.

If those four sets of digits represent candidates in four cells, and there's no other information available, there's nothing to solve within them. If those cells see each other it's a locked set, more specifically a naked quad, which allows you to eliminate those digits from external cells (as Steve said). There's nothing hidden or triple about it.

To put it bluntly, your question makes no sense with the given information. I think that's why dobrichev seemed to suspect it was written by a bot instead of a human (or so I interpreted his comment).

Within a matter of days I went from basic/medium level to extreme
...
I am doing ( trying ) the extreme because I found the other levels below it quite easy

If that's true then you should be able to formulate your question a bit more accurately. Otherwise it seems quite suspicious indeed. (What Hodoku calls "extreme" has nothing to do with real extreme, but still.)

[eddieb]

spAce, thank you for your reply. OK, based on the fact that three people appear to not comprehend my question I can only imagine that my communication skills have taken a big dive, so I'll leave it at that.

[SpAce]

spAce, thank you for your reply. OK, based on the fact that three people appear to not comprehend my question I can only imagine that my communication skills have taken a big dive, so I'll leave it at that.

If you have a genuine question, you shouldn't leave it at that. Like I said, if you can come up with a concrete example from a real puzzle, I'm sure we can figure it out. The given information is just not enough to even imagine what you're after.

[StrmCkr]

Most of synders methods for competition involved. Guess, i used to beat him regularly on practice sites but meh that was ages ago. I wouldnt worry about anything named after him as a technique as they tend to be trial and error based and ultimentlly irrelevant here.

What i can recall from his name is uniqieness arguments specifically ur type 2 he used frequently.

But as others menthioned a concrete full puzzle would help us understand your inquiry.

[SpAce]

Most of synders methods for competition involved.

The "Snyder notation" is indeed a speed-solving method, though it works for normal solving too. The idea is to fill in just the most helpful pencil marks (bilocations, bivalues) to avoid unnecessary work and cluttering the grid. I'm pretty sure most p&p solvers have used some form of it whether they've ever heard of it or not. Naming such an obvious and basic approach after a single person is a bit ridiculous, I think.

What I don't like about the original p&p version is the way it marks the bilocation candidates on the edges of the cells. While that's optimized for speed-solving, I can only assume that it makes it quite hard to upgrade to full pencil marks if they're needed. Then again, it doesn't have to be used that way. (But is it really "Snyder notation" if used otherwise? I'd say it's just common sense.)

I wouldnt worry about anything named after him as a technique as they tend to be trial and error based and ultimentlly irrelevant here.

This is just a notational technique, and very basic at that. Yet it's quite relevant for a manual (especially p&p) player, actually, and it has nothing T&E related per se. A recent example of it here.

Quite a coincidence (?) that the term came up in two posts in a row.

[StrmCkr]

Quite a coincidence (?) that the term came up in two posts in a row.

For bots not really.

The persay method was to note the bivavles for backtracking as he guess on them. Usually not needed as the grids are solvable with basics and xy wings (hence the bivavles). But more comolicated grids is whwre people get hung up.
anyhow not helpul so i digress.