done

Done

done

easy

hard? why? this is so easy, even without greens :-)

go

done, yup - very easy...

start

done

ok - just making a weird comment for the archive-searcher, but yesterdays expert - i was just looking thru the comments and then tried scanraid to solve it - yipes. just take a guess at r1c3 and for me - i guessed correctly - it all "just worked".

it took the solver like 5 or 6 passes (yes a wxyz-wing too) before it got anywher after the 13-stopping point... if orangeslicke wouldnt mind explaining what cells and the concept behind the invisible-conjugates was about - id love to hear it. just curious... have fun with todays, nothing more complicated than some pairs iirc.

sorry about the typo orangeslice, and i wonder what drwhos rating was for yesterday... :)

go

done

went green when i got stuck, got really easy then :)

go

and going green

done

hi all

pretty easy

evreyone--good morning. Did I see that someone solved yesterdays expert without guessing?? I've stared at it for more time than I care to think about.

Difficulty score 33. I don't think it really is that hard. But it is ranked a hard because naked and hidden pair analysis is needed.

drwho== is there a solution to yesterdays expert without guessing/forcing?????

I'm sure there is, but I had to guess.

gm all

Hello

Yesterday's puzzle used almost locked sets and aligned pair exclusion to remove candidates.

Done. No greens. Two unique rectangles, several naked and hidden pairs.

oh oh what was that about yesterday

i saved it to finish later

it always fascinates me how we all play to our strengths/preferences. i finished today's with no hidden pairs but i used a lot of naked triples and quads

There's (usually) more than one way to solve a sudoku :)

what is an almost locked set

When you almost have a naked/hidden triple/quad/whatever, but are one cell short.

one... cell... short... hmmmm

if i open it up will you walk me through it?

or do you forget

lol I don't think I can remember exactly what I did. It was ugly.

well the last thing i did was the x-wing krys pointed out. (which sounds like it might be "aligned pair exclusion"

hang on

I used the almost locked sets to preform aligned pair exclusion in I think two places, the second of which actually solved for a cell and opened the puzzle afterward.

would you be willing to put your email addy in your profile long enough for me to get it? and then i could send you a screencap of where i am?

Given that it's a horribly ugly technique and usually involves writing things down on a scrap of paper, there's probably a different way to solve it.

Scanraid has a very detailed explanation of aligned pair exclusion, try looking over that first.

well i think i understand the aligned pair exclusion, i am not sure about the almost locked business

what do you mean by one cell short exactly? give me an example?

An Almost Locked Set is any group of N cells (that can all see each other) with N+1 candidates between them . This includes bi-value cells. A Locked Set, by contrast, contains exactly the right number of canidates for the group, examples of which are Naked Pairs and Triples.

ok let me take a look

can they all be in the same box or whatever?

If you're doing aligned pair exclusion they do.

or same row?

Other moves, such as the "death blossom" (which I've never encountered in the wild) don't need them to be in a single box.

so for instance if i have a cell with 3 and 7, a cell with 2 and 3, and a cell with 2, 7, and 8?

DEATH blossom????? gollllly

Yes, but you want to look at only two cells.

how do i know which two i want to look at and what do i do with them?

Don't worry about the death blossom. I'm not even sure I fully understand the logic in it, but again, I've never seen one in an actual puzzle.

well i have 2 cells in one box with 2, 6, 7 in them...

Look for two cells that share two candidates, but where one cell has an 'extra' potential number.

so a two-value and a three-value cell.

only one cell has the extra, ok

ok i have a box with 2 and 8 in one cell and 1, 2, 8 in another cell

they aren't in the same row or col though, is that ok?

they have to be lined up.

ok then i'll use in the bottom left

2, 8 and 2, 8, 6

those are lined up.

now what do i do with them

Now check all the possible solutions of those two cells. Handy to open notepad or use a scrap of paper here.

but then that is just a sort of a forcing chain, isn't it?

Obviously they can't both be the same number, so all of those can be crossed out. Next you look at combinations that might remove all other candidates from another cell lined up with them or in that box.

Why? You aren't arbitrarily plugging in a number.

well, in a forcing chain you pick one of two things and see how it affects the other cells

and if that doesn't work you try the other way

We're not picking anything.

one way or another, you're trying the different possibilities

:)

hello everybody

We're saying "both of these cells can't have both of these numbers in them, because it would break the puzzle, therefore (maybe) X candidate can be removed"

ok

let me see

Hello yul

hi yul btw

i dunno i must be doing it wrong

Is this a very hard sudoku today?

all i'm thinking is, if that's a 2, and that's an 8, then that has to be a ... and that has to be a ....

today not so bad, no

Anyway, forcing chains is simply saying "I don't know what the hell to do so I am going to see if this is the right answer by GUESSING on this cell"

not exectly

I only consider it a legitimate move on sudoku that don't have a single unique solution.

i think of a forcing chain more as, this has to be one of two things. if it is this, then that means the following things happen. if that leads to an impossibility, then it CANNOT be that.

Except even those sometimes have logical ways of solving them without forcing the puzzle.

that is the way, excluding impossibles

Yes but it's a shintsy way of solving any puzzle without doing the work.

lol

so how SHOULD i be thinking about the possibilities here then

the combos that could work are 2, 8; 8, 2 or 8, 6... i don't see how that helps me.

it gives me a 67% chance that another box is the 6...

Well, once in a blue moon you can remove a candidate by doing this.

so you're saying the cells i selected might not be able to have this apply, i'm not necessarily missing something in looking at this row.

Yeah, it's an icky move and it doesn't always work.

A good set to pick is two cells that have a lot of bivalue cells they can both see, either within their box or lined up with them.

well there's the 8th column

oh I just refreshed my page by mistake... starting over

but that seems to have the same prob as the 8th row that i was just trying

The aligned bivalues need to share some candidates with your almost locked set.

right

Just throwing that out there :)

well in that case the 8th row was at least a better choice than the 8th col

i still have four or five values in a lot of the boxes in the upper middle so that's not helping

I don't often say this, but scanraid's examples for this technique are actually extremely helpful in wrapping your head around the concept.

And I have to go to school, so...

ok, ttfn OS, and ty

You'll get it eventually :)

(i love to see how large a percentage of a post i can make acronymical)

now that OS is gone...

*bangs head on piano keys*

i'll never get it, never get it, never get it!

i'm doing it wrong, all i'm doing is forcing in my head.

hershy, why not to look in simple sudoku examples, I am sure there you could find an alternative with a different name

'sok, i'm just gonna force this one

I could only force up to 8 moves in my head. If I don't exclude anything, I start at another place

yeah i'm doing it with reds

I haven't got reds :(

oh yeah i remember some people had trouble getting them

ah

I print out puzzles, if I am completely stuck

an impossibility

now where did i start this thing.... lol

:D

there, done

forcing chains are still LOGICAL... maybe this whole thing has taught me not to be so unhappy about using them...

back to today's now

have a nice day, hurshy

oh are you going, yul?

no, I thought you are talking about the day of 'today'

I get it, you are back to today's puzzle

i am talking about finishing today's sudoku now that i am done with yesterday's :)

:)

well after the morass of yesterday's puzzle, this one felt like a super-easy

oh yes :)

now i shall go and find some sets.

ttfn!

what for?

are you marking today?

Done! Used greenies and only had to guess once. Not bad.

I guess some treat puzzles as climbing mountings, where the most difficult root is the only way.

I have to admit that I would like to be like that but have to train myself for a long time before I do that.

I am of to read sudoku theory :) have a nice day everybody

Go.

Rats. Some mistake. Starting over.

Done. Nothing but crosshatch, pairs and a few loners. Pretty easy, except I always have trouble finding the loners.

go

GO

Done. No green. No guessing.

Today's wasn't too bad at all. I didn't get to do yesterday's yet, and it's not looking too happy so far at the outset.

ta da Done good day all

...

:)

:)

:)

never did finish yesterday's. :-/

That's okay - just got today's done :)

go

go

.

done

no greens, whew

done (after that first screw-up)

no greens - impressive!