## Sudoku on paper without pencilmarks

Advanced methods and approaches for solving Sudoku puzzles
when does the next one (even numbered millennia) begin? I had the date here earlier but I've lost it now! ;-)
Shazbot

Posts: 220
Joined: 24 September 2005

em, you're perfectly right about the dry bones and I'm quite fed up with the senior PGA as well. Matter of fact I'd rather do 19x19 sudokus and fill in all their pencil marks, than hear the PGA's history again.

This reminds me of a fellow named "Guest" (from outer space:?: ). I know you came across him too, but press here { EDIT: broken link: forum.enjoysudoku.com/viewtopic.php?p=14110#p14110 }. I used to appreciate his extraordinary "intralectual" powers, but in order to put things straight, I asked him if he was from Inner or Outer Mongolia. Unfortunately, he never came back again. Anyone of you an:idea: where's he now?

Now, back to our B&B the pencil marks, coz who's going to pay us after all?

It seems to me that unless we're some kind of Einstein, we'll always use some candidate representation - pencil marks or candidate tables which I suggestedelsewhere or some other system. Because the candidates are the pieces on our chessboard (the grid). Otherwise, we're probably playing blindfold Sudoku. Someone at this forum put down the problem this way: "The human brain does not have the resources to hold in short term memory all the factors necessary to resolve each cell".

Please note, I've underlined the "all", to say that there are always exceptions to the rule.

Kibitzer
Last edited by Kibitzer on Wed Dec 07, 2005 4:07 am, edited 2 times in total.
Kibitzer

Posts: 25
Joined: 17 September 2005

Don't think so! Men had the last two in a row, so now we get the next two : 1.1.2001 – 31.12.4000. That'd be fair.

Kibitzer wrote:Anyone of you an where's he now?

I think he was nuked for being a bit too far off topic.

Kibitzer also wrote:"The human brain does not have the resources to hold in short term memory all the factors necessary to resolve each cell"

Maybe it doesn’t, but it can do it in stages. It can deal with the 81 cells in groups and the interactions between a couple of groups at a time - you don’t have to memorize the whole grid at once to solve without marking.

Hud wrote:Didn't you once see Hale Irwin chip a ball out of the woods and hit it into a lake?

Fascinating! I do like the idea of crocodiles in the lakes though. Also pythons in the bunkers and carnivorous plants in the undergrowth. That’d liven it up!

Bigtone wrote:I copy what I have done 9 times and write on each copy all the available squares for 1-9

Sorry Bigtone, I’d actually rather watch PGA!
emm

Posts: 987
Joined: 02 July 2005

Thanx em for the info about "Guest". Now at least I know his whereabouts.

Maybe it doesn’t, but it can do it in stages. It can deal with the 81 cells in groups and the interactions between a couple of groups at a time - you don’t have to memorize the whole grid at once to solve without marking.

Please have a look at my post again. I edited it immediately after I sent it in.

Kibitzer
Kibitzer

Posts: 25
Joined: 17 September 2005

I don’t really want to labour the point, Kibitzer, but I don’t agree with your edited (!) post either. I think the human brain can hold in short term memory all the factors necessary to resolve each cell. What it can’t do is hold in short term memory all the factors necessary to resolve every cell. Is that what you meant?

It’s not about exceptions to the rule. We can all do this, with different degrees of ease, if we choose.

Last word on this - I took a random hard puzzle and solved it with candidates, then re-solved it without marking. The difference in time taken was exponential! – even though I had already done it once. This tells you something about my memory - but the point is, this is not the method for you if speed matters.

Absolutely last word – even though I couldn’t visualise all the candidates at the same time, I actually felt I had a better idea of the whole picture the pencil-free way. Not sure how that figures, it just felt like it.
emm

Posts: 987
Joined: 02 July 2005

em wrote:I think the human brain can hold in short term memory all the factors necessary to resolve each cell. What it can’t do is hold in short term memory all the factors necessary to resolve every cell. Is that what you meant?

Ya, that's what I meant, although for the time being, (which may turn out permanent) I still can't visualize mentally a swordfish etc. pattern, even if I know it's in there.

Now it's time, I suppose, to ask Shazbot who's initiated this topic, if possible, to speak up

Kibitzer
Kibitzer

Posts: 25
Joined: 17 September 2005

zzzzzzzzzzzz

Oops - sorry - I feel asleep at the PGA conversation stage.... I'm quite happy reading all your thoughts without saying much - after all, I did post the question to learn what you all did.

I was still thinking I probably don't have what it takes (patience and time) to work out any but the most simple puzzles on paper without pencilmarks, and I admire those who do. But I think I felt better after reading em's comment:
em wrote:this is not the method for you if speed matters
While I don't time myself anymore (SS doesn't show time taken, but I WAS interested intensely in how long I took when I was using Pappocom Sudoku and continually trying to beat my best times), I do like to get them completed quickly. The excitement of having a correct, finished puzzle far outweighs the challenge of getting there - I'm not willing to spend a couple of hours working it out. So I guess I don't feel so guilty anymore about using the "show candidates" or "highlight candidate Xs" in SS (I still avoid hints unless I'm totally stumped). And if I can do it using an Xwing or swordfish or colouring, then that adds to the fun of it all.

But when I have an idle moment or two or three, and no access to the computer (viz DH is hogging it), at least I now know a very good way of pencilling in when I do get stuck. And I find now if I ignore the pencilmarks in the program and concentrate solely on the clues, I can usually fill in a few more numbers more quickly at the start (think that was mentioned in the last day or two in another thread).

Shazbot

Posts: 220
Joined: 24 September 2005

Anyone interested to know how to do pencil marks on the actual grid provided on the newspaper. with each cell being 7.5 sq mm.
Jeff

Posts: 708
Joined: 01 August 2005

sweetbix

Posts: 58
Joined: 10 December 2005

Sweetbix,

what, the PGA Tour (snoooze) or the method of solving a sudoku puzzle

oops have i opened up another can of worms
Crazy Girl

Posts: 189
Joined: 08 November 2005

Crazy Girl wrote:Sweetbix,
what, the PGA Tour (snoooze) or the method of solving a sudoku puzzle
oops have i opened up another can of worms

Hi, Crazy Girl. I thought Sweetbix was interested in the pencilmarks. Should I post it or not? What worms?

Here is how I put pencilmarks on a grid. It allows me to solve 98% of the puzzles directly on newspapers. In order to fit the pencilmarks in the tiny squares, 9 symbols are used to represent the candidates 1 to 9, each of which should be marked in a specific position similar to a telephone keypad as follows:

Once a candidate has been eliminated, the corresponding symbol in the square should be coloured in like this:

For an ongoing puzzle, the pencilmarks in a box should look like this:

It will take 2 or 3 puzzles to familiar with the symbols. With practice, you should be able to subconciously visualise these symbols as digital pencilmarks to make deductions using more advanced techniques.
Jeff

Posts: 708
Joined: 01 August 2005

Jeff wrote:Anyone interested to know how to do pencil marks on the actual grid provided on the newspaper. with each cell being 7.5 sq mm.

How do you get all that into a square whose sides are only about 2.7 mm long?
r.e.s.

Posts: 337
Joined: 31 August 2005

Hi Jeff,

Thanks a lot. I liked your system very much. It’s elegant and it’s of course a great improvement over pencil marks, because instead the mess of rubbing out, you "color" the symbols "out". Besides, as you say, some squares are too small for pencil marks anyway. I’m sure that after some practice, one can make good use of it.

In case you have'nt seen the system which I suggested elsewhere, press here . It looks very different, because cell analysis is done externally, but the principle is the same - whenever all values but one are crossed out from the square/box/row or column, the cell is solved.

I thought that this topic was already dead but I was mistaken. It keeps on surfacing on and on, which proves that the problem is a real one. Thanks to Sweetbix and Crazy Girl who made it happen.

Kibitzer
Last edited by Kibitzer on Wed Dec 14, 2005 3:16 am, edited 3 times in total.
Kibitzer

Posts: 25
Joined: 17 September 2005

Jeff,

the topic so far has talked about pencilmarks and (somehow) the Golf PGA tour. So 'this' could refer to either of the above.

besides, I was merely adding some English Humour to this forum.

Like your method, something new and a different view. Can you see X-wings and stuff more clearly with this technique?
And what sort of time does it take to solve a typical Fiendish with this method?
Crazy Girl

Posts: 189
Joined: 08 November 2005

Pat wrote:in my English, "he", like "they", gives no indication of female/male.

Consult your English teacher for more input.

When referring to a specific person, "he" ALWAYS meant male since English became a language.

Tell Smith when he comes in that....

That would be totally incorrect if Smith were female.

"He" and "man" are only gender independent (in English now considered outdated) for discussions where there is no specific person.

"Man cannot live by bread alone" implies "Human beings ...."

"The driver should not hold objects in his hand. He should keep both hands on the wheel." implies "his/her hand" and nowadays people tend to use the latter. English, like any language, changes with time.

Why the fuss? Because of stuff like this you used to see in the 1950's:

The doctor should tell his nurse what he expects of her.
The boss should tell his secretary where she can find her office supplies"

Note that one never saw
The doctor should tell his nurse what he expects of him.
The boss should tell his secretary where he can find his office supplies"

Proving that "he" had already lost its usefulness as a gender neutral pronoun. It was used to insist that positions of importance were held by males. A person who still insists today that it is correct usage should examine his motives. (That's right: "his")

Mac
QBasicMac

Posts: 441
Joined: 13 July 2005

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