Was Samurai number 19 much more difficult than usual or ...

This is the place to complain about the latest <a href="http://www.sudocue.net/samurai.php">Samurai</a> or boast about being in pole position in the list.
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Brian
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Was Samurai number 19 much more difficult than usual or ...

Post by Brian »

Was Samurai number 19 much more difficult than usual or did I miss something obvious? At first it seemed easier than usual, and lots of numbers fell into place, but suddenly, I got stuck. I repeatedly went around all the puzzles searching for the usual suspects, XY-wings, hidden pairs, etc., but found nothing. :roll:

In then end I found an XY-chain in the bottom right puzzle that established that if there was not an 8 in R3C2 the had to be a 2 in R1C1, and vice versa. Looking at the middle puzzle, this meant that there was either an 8 in R9C8 or a 2 in R7C7. A 2 in R7C7 implies a 6 in R3C7 and an 8 in R9C8 means a 3 in R6C8, an 8 in R6C9 and a 5 in R1C9. So, using an XY-chain that spanned two puzzles I can see that if there is not a 6 in R3C7 there is a 5 in R1C9 and vice versa. If there is a 5 in R1C9 there is only one cell left in the box for an 8, R1C7. So, there must either be an 8 in R1C7 or a 6 in R3C7. But if there is an 8 in R1C7 there is only one cell left in the box for a 6, R3C7. So there must either be a 6 in R3C7 or a 6 in R3C7 :lol: Then the rest of the puzzles quickly fell into place.

At the top of the Samurai Contest page Ruud has written, “These can be solved with singles, line-box interactions, naked and hidden subsets and an occasional X-wing.” So I think I must have missed something simple. Could anyone point it out for me please?

Here is where I got to with each of the puzzles:

Top Left:

.------------------.------------------.------------------.
| 8 247 1 | 3 247 6 | 479 5 479 |
| 6 2347 24 | 5 247 9 | 1478 13478 13478|
| 9 347 5 | 47 1 8 | 2 3467 3467 |
:------------------+------------------+------------------:
| 457 1 6 | 2 478 3 | 478 9 4578 |
| 3 8 24 | 147 9 5 | 6 1247 147 |
| 457 245 9 | 6 478 147 | 3 12478 14578|
:------------------+------------------+------------------:
| 15 9 7 | 8 6 12 | 145 13 1234 |
| 145 45 8 | 179 3 127 | 1579 167 12679|
| 2 6 3 | 1479 5 147 | 1789 178 1789 |
'------------------'------------------'------------------'

Top Right:

.------------------------.------------------------.------------------------.
| 1 345 6 | 58 9 358 | 7 2 34 |
| 23459 23459 7 | 125 6 1235 | 358 158 134 |
| 235 8 235 | 4 7 1235 | 356 156 9 |
:------------------------+------------------------+------------------------:
| 2345789 2345679 23589 | 25789 238 25789 | 1 89 67 |
| 23789 2379 1 | 6 238 2789 | 89 4 5 |
| 5789 5679 589 | 5789 1 4 | 2 3 67 |
:------------------------+------------------------+------------------------:
| 5678 157 58 | 1279 4 1279 | 3569 1569 123 |
| 357 1579 359 | 12789 28 6 | 4 159 12 |
| 26 129 4 | 3 5 19 | 69 7 8 |
'------------------------'------------------------'------------------------'

Middle:

.------------------.------------------.------------------.
| 145 13 1234 | 12 67 9 | 5678 157 58 |
| 1579 167 12679| 12 4 8 | 357 1579 359 |
| 1789 178 1789 | 3 67 5 | 26 129 4 |
:------------------+------------------+------------------:
| 17 5 17 | 6 8 3 | 9 4 2 |
| 38 2 38 | 4 9 1 | 57 6 57 |
| 46 9 46 | 7 5 2 | 1 38 38 |
:------------------+------------------+------------------:
| 69 67 79 | 8 3 4 | 25 25 1 |
| 13 138 138 | 5 2 6 | 4 79 79 |
| 2 4 5 | 9 1 7 | 38 38 6 |
'------------------'------------------'------------------'

Bottom Left:

.---------------.---------------.---------------.
| 5 2 8 | 3 4 1 | 69 67 79 |
| 7 4 9 | 2 6 5 | 13 138 138 |
| 6 1 3 | 7 8 9 | 2 4 5 |
:---------------+---------------+---------------:
| 2 8 1 | 9 5 7 | 346 36 34 |
| 4 3 5 | 6 12 8 | 19 127 1279|
| 9 7 6 | 4 12 3 | 5 128 128 |
:---------------+---------------+---------------:
| 1 9 24 | 8 7 6 | 34 5 234 |
| 3 6 7 | 5 9 24 | 8 12 124 |
| 8 5 24 | 1 3 24 | 7 9 6 |
'---------------'---------------'---------------'

Bottom Right:

.---------------.---------------.---------------.
| 25 25 1 | 3 8 4 | 7 6 9 |
| 4 79 79 | 5 1 6 | 2 3 8 |
| 38 38 6 | 2 7 9 | 4 5 1 |
:---------------+---------------+---------------:
| 379 379 5 | 1 39 8 | 6 2 4 |
| 1 23 4 | 6 35 25 | 8 9 7 |
| 289 6 289 | 47 49 27 | 3 1 5 |
:---------------+---------------+---------------:
| 578 4578 3 | 9 6 57 | 1 478 2 |
| 6 2457 27 | 8 245 1 | 9 47 3 |
| 2789 1 2789| 47 24 3 | 5 478 6 |
'---------------'---------------'---------------'

Thanks,

Brian.
lynn893
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Post by lynn893 »

Brian,

I got to the exact same place as you did before I also struck the proverbial 'rock wall'.

Since I'm not skilled at xy chains :oops: , I ended up taking a logical guess (bifurcate) on an x-wing in grid 3 - r1c3/r2c3 on the 2's and it ended up falling into place for me from there.

I would also like to hear if anyone else who does these samurai puzzles hit the wall at this point, and what technique they used to break the puzzle from here.

Thanks!
Marlie
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Location: Venray Netherlands

Post by Marlie »

I am not sure if it was at this point but i got stuck also.
so i started again and filled all with logical steps. :oops:
Glyn
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Post by Glyn »

Not terribly hard, but there were a couple of moves you missed.

Column 9 Bottom Left Hidden Pair. (No help at all) &
Column 3 Middle Grid Hidden Triplet. (Gets a Hidden single, then go to the bottom left grid do as much as you can, then back to middle grid to finish).
I have 81 brain cells left, I think.
Sarah
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Post by Sarah »

It was the associated quint which caught my eye, but all the same after the wash.
Brian
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Post by Brian »

Thank you Glyn for pointing out what I missed. I see them now and wonder how I could have missed them. :oops:

It just shows I should be more thorough when searching for easy ways to eliminate candidates in these puzzles before resorting to techniques more typical of the Sunday Daily Nightmare. :twisted:

Brian.
Pete
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Post by Pete »

No matter how hard or easy the puzzles are that Nougie Bauer gets them before me...
Im embarassed and humiliated.
I may just give up.
"It gets dark at night" - Olbers
Marlie
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Post by Marlie »

Pete wrote:No matter how hard or easy the puzzles are that Nougie Bauer gets them before me...
Im embarassed and humiliated.
I may just give up.
Why? Just because someone uses a programm?
Maybe now you can understand what i am thinking last year about people like that. :D
Pete
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Post by Pete »

I know theres better programmers than me... like Ruud.
Nouggie may be one of those.

if you have dos, you can use gwbasic.
if you have windows they came with Qbasic.
Then there is XP that comes as an empty gui.
Notepad doesnt overtype anymore, you cant replace TAB with Space.
tempts me to use delphi just because it has a text editor.

I prefer Pascal... so i got Delphi. an excellent program. It also does c and windows.

I just taught it to do puzzles other than the 9x9.

Any of the Hard puzzles, my program cant handle.
It can handle naked pairs, hidden singles and some intersections.
So its a bit smater than clueless helper.

Its a jack of all trades, and master of none.

I think I finally understand naked triples and xwings well enough to program those.

Currently Im working on revamping the cage sums.

As always anyone is welcome to a copy...
shipped quickly by email...


btw when i made it do 3x3 to 9x9 puzzles it no longer recognized clueless or samurai as 9x9 in a group hence my 2 hour samurai last week.
Clueless helper would have been a lot faster but i just had to Fix it.
"It gets dark at night" - Olbers
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