The New Sudoku Players' Forum

[udosuk]

I guess Cathy should have already figured out this next time she looks up here, and if she hasn't then she'll need this pointer anyway: the next logical step is to look at the cages in the 4th box and 7th box. A hidden single of 2 will emerge soon...

[emm]

Yep, I got the 2 and the 6 in row 4 and the 2 in row 1 ... then what???

Aha, a naked quintle in row 1 - could be leading somewhere...

[CathyW]

Yes I found the 2 - thanks!! And was making good progress, or so I thought!

So near and yet so far , I obviously went wrong somewhere else as I ended up with two 3s in the 45-cage that overlaps box 5. But I won't be defeated (yet) and will try again.

[emm]

Yes! I think the quintle is the key – r1c1 must be 8 otherwise no place for 8 in col 1 => locks 7 into r2 box 2 => cages of 3 must = 10.

Don’t tell me! I’m taking it to work again and if it all falls apart this time I’ll beg for answers.

[emm]

I haven’t done Killers before – this probably wasn't a very good place to start!

Progress report -

Code: Select all


 8     7   2    | 9      5    14   |  14  6   3
 145   6   145  | 37     37    8   |  9   14  2
 134   9   134  | 14     6     2   |  5   8   7
----------------+------------------+---------
 345   2   6    | 345    8     9   |  7   345 1
 1345  8   9    | 123457 12347 134 |  234 345 6
 7     13  1345 | 12345  1234  6   |  234 9   8
----------------+------------------+--------------------
 2     13  13   | 6      9     5   |  8   7   4
 6     5   8    | 24     24    7   |  13  13  9
 9     4   7    | 8      13   13   |  6   2   5

[emm]

I haven't got a 2 in box 5. That's it - I'm going to bed.

[udosuk]

So your last "progress report" wasn't entirely correct. Scratch that and go back to the point where you determined r1c1=8 (it was a total mistake to lock 7 in row 2 block 2). Now here is the tricky step:

Because of the 9-cell cage overlapping block 5, 2 pair of cells must contain identical numbers. One pair you already fixed up as 6. For the other pair, although you couldn't determine their value yet, at least you could "synchronize" their candidates... Then you'll find some hidden singles. The rest should be more "trivial".

[emm]

So your last "progress report" wasn't entirely correct.

It was nice of you to put it like that udosuk – actually I had to backtrack through 27 moves to get back to the 8 in c1. Talk about Ariadne’s thread! Is this perseverance or stupidity? There’s no need to answer.

[CathyW]

Oh I think perseverance has to be the answer Em. I've finally cracked it - only took 6 days on and off Not sure I can take too many of these because of the time involved - though maybe the next one will seem easier after this. Thanks to Paul and Udosuk for the tips - I'd like to think I would have got there on my own eventually but probably not for another several days

[emm]

Eureka! The hint about the cage of 9 did the trick. Thanks v much for your help, udosuk, like Cathy I’m going to think twice before venturing into this again.

Interestingly, you can reach a Sudoku solution from my progress report. My 14yr old presented me with a perfect completed grid this morning which he’d finished by T&E - neglecting just once to follow the Killer rule (with my misplaced 2 in box 5). Was that a consolation? Probably not for my intelligence, but his grin was reward enough for the brain pain. Would I tell him about his mistake? Not on your life!

Anyway, thanks a lot for your hints & Cathy and Paul too. Thread re-gathered, Minotaur slain, Theseus going shopping!

[udosuk]

I'm sure you guys will get better and better with these. The key is more practice. Djape's site is a good place where you'll get a "daily killer" sudoku puzzles 5 days a week now. Make no mistake, the average difficulty of these makes the daily ones posted by The Times look like child's play...

2 things:
1. Went to Ms Misawa's blog, discovered that these puzzles are described in wikipedia.

2. Read some comments in this article in the blog, looks like Ms Misawa has noticed our innocent discussion here, and maybe she has a problem with us posting the problem directly here (I'm gonna take off the pic in the other thread right now). Not too good in understanding all those Japanese, and here is the translation from Atlavista Babelfish:

The equal sign non- equal sign sum nun which some days ago was raised pre- thing, was written on the Sudoku forum, (also problem being reprinted, no permission it increased). The person who is not unravelled, being to request hint from the person who is unravelled it does, but you cannot explain the method of solving it seems. With however it arrived to the answer, it solved the fact that you say and, as for muscle was not understood (it solved with the louse crushing) kana? That and, this problem (2nd question) the name, "daemon" was written is also exactly. From naming, the kind of air to which the thinking which is not unravelled is transmitted does. Still because it seems that trial and error is done, after already doing the method of solving for a while, the one which it raised is good kana?

Your guess is as good as mine...

[CathyW]

Oh dear - I thought Ms Misawa might be pleased because we would have encouraged others to go and have a look at the site and to try out this new form of sum number place a.k.a. Killer Sudoku.

I found Djape's site back in September and have been doing his Killers ever since - I enjoy them much more than the offerings from The Times (although I have to do the puzzle anyway!). Even today's so called 'Tough' wasn't but I guess they are trying to cater for the masses and maybe practice has enabled me to remember and spot the possible number combinations more quickly.

Em - you certainly went in at the deep end having not done other Killers before

[PaulIQ164]

Oi! I couldn't do today's Times Killer. Maybe I was being thick though - I'll have another look later.

[emm]

I wouldn't say you’re thick, Paul … maybe just a little unravelled.

[PaulIQ164]

Well, you'll be thrilled then to know that I did get around to doing it - and I messed it up!