Sudoku on paper without pencilmarks

Advanced methods and approaches for solving Sudoku puzzles

Sudoku on paper without pencilmarks

Postby Shazbot » Fri Dec 02, 2005 6:36 am

I want to learn from those of you who manage to solve advanced puzzles on paper without the need for pencilling in candidates - how in the world do you do it?

At best I could probably find naked and hidden singles and locked candidates. How do you manage the likes of hidden/naked pairs/triples/quads, through to xwings, swordfish and colouring?

Did you USED to pencil candidates in then just improved over time to the point where SEEING them there was no longer needed? Or is this ability limited to only those with a photographic memory or an IQ in the top 10%, meaning I needn't bother tormenting myself anymore?
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Postby stuartn » Fri Dec 02, 2005 3:51 pm

Pure doggedness I'm afraid! - I can usually complete the Times fiendish without pencilmarks now - but it's after a year of practice. Staring hard at the beast all the way from Brighton to London (on the train) usually cracks it .

:)

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Postby Kibitzer » Sat Dec 03, 2005 2:55 pm

Hi Shazbot,

There's a reply waiting for you here for some days now.

and Shazbot wrote:
I want to learn from those of you who manage to solve advanced puzzles on paper without the need for pencilling in candidates - how in the world do you do it?


I've asked a similar question as yours here. It was directed to em and got from him an interesting reply immediately following. You may have a look at it and judge for yourself.

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Postby Shazbot » Sat Dec 03, 2005 11:08 pm

Thanks Kibitzer - I'll take a look - I thought I remembered this topic discussed some time ago.
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Yes, I have seen that thread before, but not picked up the bit in em's post about USED TO have pencilmarks all over the place, and resorting to a program to pick up xwings and the like. THAT'S comforting, to know em's a mere mortal like the rest of us (though I HAD assumed em was a SHE - em I know you'll sort us out on that one really quickly as I picked you up on the same thing just a few days ago).

I'm going to try your method now and see how far I can get.
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Postby Jeff » Sun Dec 04, 2005 5:16 am

Kibitzer wrote:It was directed to em and got from him an interesting reply immediately following.

Just to keep the record straight, Em is a her with a great logical mind. We tend to assume everyone is male until it is proven otherwise!
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Postby Kibitzer » Sun Dec 04, 2005 10:26 am

Jeff wrote:We tend to assume everyone is male until it is proven otherwise!


Sorry Jeff, I had no clue. I'll be more careful next time.

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Postby Pat » Sun Dec 04, 2005 2:50 pm

Jeff wrote:We tend to assume everyone is male until it is proven otherwise!

in my English, she indicates female,
whereas he (like they) gives no indication of female/male.
i'm sorry if other people use English differently.
- Pat
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Postby Shazbot » Sun Dec 04, 2005 11:13 pm

unless there's nothing in the thread you're reading to incidate whether the person in question IS a he or a she.... We often make an unconcious decision (assume) a person is male or female based on their id or something they've written (I'm not sure if the majority assume people are male though) - and often end up embarrassing ourselves when the truth is pointed out to us.

In this case, Kibitzer wrote HE - I assumed the opposite, Jeff sorted it out. Are you coming down on HIM (male - I CAN assume that based on his name, whereas em could be a name OR initials) for giving the correct answer to a question?
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Postby lunababy_moonchild » Sun Dec 04, 2005 11:24 pm

Interesting.

I can also confirm that Em is definitely female. I can also say that I don't assume gender at all - unless the login is gender specific like Jeff or stuartn - and when I'm not sure I type s/he which works pretty well.

Anyway, back to the topic at hand:D

Luna *Pat, of course, could be either*
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Postby emm » Mon Dec 05, 2005 12:06 am

Pat wrote:in my English, she indicates female, whereas he (like they) gives no indication of female/male.

In that case I'd put a fiver on Pat being male.

Luna wrote:I can also confirm that Em is definitely female

Ooooh, I might be bicurious! I'm certainly not worried about being mistaken for the wrong kind on the internet .:D
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Postby Kibitzer » Mon Dec 05, 2005 8:36 am

If some interplanetarian lands on our planet and enters this topic, he/she (it?) will certainly ask himself/herself/itself: "Hey, is this forum really about Sudoku we've been playing out there since times immemorial"?:(

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Postby emm » Mon Dec 05, 2005 1:25 pm

Kibitzer, I suspect that some people will agree with you but to me these little off-topic side shoots are the human side of the forum. We can’t live by forcing chains alone, after all. We’re not interested only in r19c19 and we don’t all have something to add to what’s already been said in p1-34 of Sudoku Maths.

It seems to me that more and more space in this forum is being dedicated to esoteric maths threads that are so far removed from the ordinary person’s experience of Sudoku that they may as well have come from the outer limit of outer space. We need some of this human stuff for balance - to stop the forum becoming as dry as a bone and less interesting than reruns of senior PGA to most of us.

And anyway, the intergalacticans, who’ve been solving Sudoku since time immemorial, will quite likely find the human stuff a helluva lot more interesting than the maths which they could be starting to find a bit old hat!:D

Referring back to the OP – I’m not a great mathematician and yet I think that singles, pairs, triples and locked candidates are eminently findable without pencilling in candidates.
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Postby Bigtone53 » Mon Dec 05, 2005 4:37 pm

in my English, she indicates female,
whereas he (like they) gives no indication of female/male.


Hmmm. A quick survey here at work (London UK) suggested that 100% of females see 'he' as being male and close to 100% of males did not understand what the issue was.

Anyway, back to the subject. I dislike pencilling things in although if I am not going to be able to do it in one session, I tend to write in locked pairs. Where I really cheat is when I grind to a complete standstill with say a Times Superior, I copy what I have done 9 times and write on each copy all the available squares for 1-9. It makes X-Wings in particular stand out like dogs b----, but not much good for puzzles that do not use X-wings and beyond.
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Postby Hud » Mon Dec 05, 2005 4:45 pm

em, you pretty much said what I've been thinking. I'm pretty new at this game and just like to solve using usual techniques at present.

It seems to me that more and more space in this forum is being dedicated to esoteric maths threads that are so far removed from the ordinary person’s experience of Sudoku that they may as well have come from the outer limit of outer space. We need some of this human stuff for balance - to stop the forum becoming as dry as a bone and less interesting than reruns of senior PGA to most of us.

I take exception with the Senior PGA being dull though. Didn't you once see Hale Irwin chip a ball out of the woods and hit it into a lake? I think they should have made him dive in for it. Maybe they could have called his brother Steve Irwin to do it for him in case of crocodiles. Sorry to digress, but I wanted to confuse the extraterrestrials.
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Postby tso » Mon Dec 05, 2005 10:22 pm

It depends on the particular puzzle whether you'll likely be able to find something like a useful x-wing without pencil marks. It may be that you'll be able to see the x-wing (or triple, etc), but if the deduction allowed is only an exclusion and won't give you an instant "big" number, then yes, your weak link will be how much you can keep in your head at once. On the other hand, there are many situations in which a deduction will be easier to identify *before* you fill up the grid with pencil marks.


"She" is always female, but I make the political choice of using it when a lesser writer would pretend that that using "He" in somehow generic and inclusive. It isn't. Men pretend that women don't mind. Women don't speak up for fear of being ridiculed as petty. I am sick of reading disclaimers at the beginnig of books explaining that its just to difficult or confusing to use "s/he" so please forgive me for using "he". It's one thing in a Sudoku forum, but published authors ought to be able to figure it out.

How about this: In even numbered millennia, we use "her" and "she".
Last edited by tso on Mon Dec 05, 2005 8:19 pm, edited 2 times in total.
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