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daj95376
Joined: 23 Aug 2008
Posts: 3854
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 Posted: Thu Jun 11, 2009 4:30 pm Post subject: Puzzle VH_037 |
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| Code: | +-----------------------+
| 3 . . | 1 2 7 | . . 5 |
| . . . | . . . | . . 6 |
| . . 2 | 5 6 . | 3 . . |
|-------+-------+-------|
| 5 . 7 | . 1 2 | . . . |
| 2 . 6 | 9 5 . | . . . |
| 1 . . | 7 . 4 | . . . |
|-------+-------+-------|
| . . 4 | . . . | 1 . 3 |
| . . . | . . . | . 2 . |
| 6 1 . | . . . | 4 . 9 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site
If you're looking for more of a challenge: [r1c1]<>3
| Code: | +-----------------------+
| . . . | 1 2 7 | . . 5 |
| . . . | . . . | . . 6 |
| . . 2 | 5 6 . | 3 . . |
|-------+-------+-------|
| 5 . 7 | . 1 2 | . . . |
| 2 . 6 | 9 5 . | . . . |
| 1 . . | 7 . 4 | . . . |
|-------+-------+-------|
| . . 4 | . . . | 1 . 3 |
| . . . | . . . | . 2 . |
| 6 1 . | . . . | 4 . 9 |
+-----------------------+
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Play this puzzle online at the Daily Sudoku site |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Fri Jun 12, 2009 12:24 pm Post subject: |
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The first "easy" one took me five steps: | Quote: | sky 8
w-wing 98
x-wing 7
w-wing 78
sky 8 |
Now on to the challenge.  |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Fri Jun 12, 2009 1:15 pm Post subject: |
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Th4 challenge is true to its name: | Code: | x-wing 7
xyz-wing 798
got me here
*-----------------------------------------------------------*
| 3489 6 389 | 1 2 7 | 89 489 5 |
| 789 5 1 | 34 348 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
|-------------------+-------------------+-------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|-------------------+-------------------+-------------------|
| 79 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 349 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
*-----------------------------------------------------------*
I can see a ur 34 that makes r28c5<>3
but after that I am lost except for some xy-chains and more
...help |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Fri Jun 12, 2009 2:59 pm Post subject: |
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After the UR on 34s there is a sashimi sword on 3s. (vertical).
That doesn't help much. You may spot a transport on 9s if you see the useless xy wing 489. That eliminates a 9 in r3c1.
That is as far as I got. Good luck! |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jun 12, 2009 4:55 pm Post subject: |
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RE: The Challenge version puzzle
Awhile back, Keith asked if my puzzles were minimal. I gave a boring explanation for why they often weren't. I'm sure it put everyone to sleep.
For fun, I was testing various puzzles to see if removing symmetric given(s) left a viable puzzle. While checking this puzzle, I discovered that removing one given was a much better answer to Keith's query.
| Code: | r2 b2 Locked Candidate 1 <> 3 [r2c1]
r2 b2 Locked Candidate 1 <> 4 [r2c18]
c2b4 Locked Candidate 1 <> 4 [r3c2]
r4 b6 Locked Candidate 1 <> 9 [r4c2]
c5b8 Locked Candidate 1 <> 9 [r2c5]
c29 X-Wing <> 7 [r3c18],[r8c15]
XYZ-Wing [r2c8]/[r1c7]+[r9c8] <> 8 [r13c8]
+--------------------------------------------------------------+
| 3489 6 389 | 1 2 7 | 89 49 5 |
| 789 5 1 | 34 348 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
|--------------------+--------------------+--------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|--------------------+--------------------+--------------------|
| 79 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 349 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
+--------------------------------------------------------------+
# 60 eliminations remain
<34> UR Type 4 [r28c45] <> 3 [r28c5]
<49> UR [r13c18] <> 9 [r1c1] (extraneous)
[r1c1]=9 ( [r1c7]<>9 [r1c8],[r3c1]=4 [r7c1]=7 ) [r2c1]<>7 [r2c8]=7 [r3c8]=9
+--------------------------------------------------------------+
| 348 6 389 | 1 2 7 | 89 49 5 |
| 789 5 1 | 34 48 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
|--------------------+--------------------+--------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|--------------------+--------------------+--------------------|
| 79 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 49 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
+--------------------------------------------------------------+
# 57 eliminations remain
(7)r2c1 = r7c1 - (7=9)r7c5 - (9=4)r8c5 - (4=8)r2c5 => [r2c1]<>8
(7)r3c2 = r8c2 - (7=8)r8c9 - r8c1 = r123c1 - (8)r3c2 => [r3c2]<>8
b1 Naked Pair <> 79 [r1c13],[r3c1]
c1 Naked Pair <> 79 [r138c1]
b7 Naked Pair <> 38 [r8c2]
r1 b3 Locked Candidate 2 <> 9 [r23c8]
c8 Naked Pair <> 78 [r45c8]
c38r9 Skyscraper/Sashimi X-Wing <> 8 [r1c7]
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I can't find wapati's Sashimi Swordfish on <3> after the URs, but there's a finned Franken Jellyfish on <8> if anyone wishes to look for it. 
Last edited by daj95376 on Fri Jun 12, 2009 7:57 pm; edited 1 time in total |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Fri Jun 12, 2009 7:18 pm Post subject: |
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| daj95376 wrote: | RE: The Challenge version puzzle
Awhile back, Keith asked if my puzzles were minimal. I gave a boring explanation for why they often weren't. I'm sure it put everyone to sleep.
For fun, I was testing various puzzles to see if removing symmetric given(s) left a viable puzzle. While checking this puzzle, I discovered that removing one given was a much better answer to Keith's query.
Trust me, the logical solution is not pretty!!! BTW: I believe Dan's PM should be ...
| Code: | c29 X-Wing <> 7 [r3c18],[r8c15]
XYZ-Wing [r2c8]/[r1c7]+[r9c8] <> 8 [r13c8]
+--------------------------------------------------------------+
| 3489 6 389 | 1 2 7 | 89 49 5 |
| 789 5 1 | 34 348 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
|--------------------+--------------------+--------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|--------------------+--------------------+--------------------|
| 79 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 349 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
+--------------------------------------------------------------+
# 60 eliminations remain
<34> UR Type 4 [r28c45] <> 3 [r28c5]
<49> UR [r13c18] <> 9 [r1c1] ...
[r1c1]=9 ( [r1c7]<>9 [r1c8],[r3c1]=4 [r7c1]=7 ) [r2c1]<>7 [r2c8]=7 [r3c8]=9
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I can't find wapati's Sashimi Swordfish on <3> after the URs, but there's a finned Franken Jellyfish on <8> if anyone wishes to look for it. |
I don't see the 49 ur.....can you help? |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Jun 12, 2009 8:19 pm Post subject: |
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I found a swordfish on 7, which was the compliment of the x-wing 7,
the xyz-wing 789,
the UR34,
I never saw the UR49; I have never considered that form of forcing non-uniqueness.
I did find an additional deletion: an extended xyz-wing 389 with pivot in r8c1 and bivalue 38 in r9c3; the extension (or chain) to delete the 8 in r8c2 is: (9)r8c1 - (9=7)r7c1 - (7=9)r7c5 - (7)r9c5 = (7)r9c8 - (7=8)r8c9; r8c2<>8.
I will rest before I try further.
Ted |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Fri Jun 12, 2009 8:27 pm Post subject: |
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| arkietech wrote: | | I don't see the 49 ur.....can you help? |
It's ugly but present. The implication chain was suppose to help, but I'll provide an extended explanation.
| Code: | +--------------------------------------------------------------+
| 3489 6 389 | 1 2 7 | 89 49 5 |
| 789 5 1 | 34 348 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
|--------------------+--------------------+--------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|--------------------+--------------------+--------------------|
| 79 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 349 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
+--------------------------------------------------------------+
# 60 eliminations remain
<49> UR [r13c18] <> 9 [r1c1] (extraneous to solution)
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Important strong links:
| Code: | (4)r1c1 = (4)r1c8
(4)r1c1 = (4)r3c1
(7)r2c1 = (7)r2c8
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Important eliminations and assignments caused by [r1c1]=9
| Code: | (9-4)r1c1 = (4)r1c8
(9-4)r1c1 = (4)r3c1
+--------------------------------------------------------------+
| =9 6 389 | 1 2 7 | 8-9 =4 5 |
| 789 5 1 | 34 348 389 | 2 789 6 |
| =4 789 2 | 5 6 89 | 3 149 1478 |
|--------------------+--------------------+--------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|--------------------+--------------------+--------------------|
| 7-9 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 349 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
+--------------------------------------------------------------+
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To complete the unacceptable <49> UR in [r13c18]:
| Code: | (9)r1c1 - (9=7)r7c1 - (7)r2c1 = (7-9)r2c8 = (9)r3c8
+--------------------------------------------------------------+
| =9 6 389 | 1 2 7 | 8-9 =4 5 |
| 89-7 5 1 | 34 348 389 | 2 =7 6 |
| =4 789 2 | 5 6 89 | 3 =9 1478 |
|--------------------+--------------------+--------------------|
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 389 389 | 7 38 4 | 5 6 2 |
|--------------------+--------------------+--------------------|
| =7 2 4 | 8 79 6 | 1 5 3 |
| 389 3789 5 | 34 349 1 | 6 2 78 |
| 6 1 38 | 2 37 5 | 4 78 9 |
+--------------------------------------------------------------+
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In this case, the strong links on <4> only left showing that [r1c1]=9 somehow forces [r3c8]=9 ... and the unacceptable UR.
Final Note: This puzzle has a very difficult solution, which I posted as an update to my message above. It was meant to demonstrate why my puzzles are often not minimal !!! |
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arkietech
Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA
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| Posted: Fri Jun 12, 2009 9:42 pm Post subject: |
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Danny,
I have learned something today. Still working on what it is.
I have yet to figure out whether either minimal or symmetical are needed to make a good puzzle. I have got a lot to learn. |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Fri Jun 12, 2009 11:05 pm Post subject: |
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| daj95376 wrote: |
I can't find wapati's Sashimi Swordfish on <3> after the URs, but there's a finned Franken Jellyfish on <8> if anyone wishes to look for it. |
Well, this one woke us up, well done daj!
| Code: | .------------------.------------------.------------------.
|*3489 6 *389 | 1 2 7 | 89 489 5 |
| 789 5 1 | 34 48 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
:------------------+------------------+------------------:
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 89#3 *389 | 7 *38 4 | 5 6 2 |
:------------------+------------------+------------------:
| 79 2 4 | 8 79 6 | 1 5 3 |
|*389 789-3 5 | 34 49 1 | 6 2 78 |
| 6 1 *38 | 2 *37 5 | 4 78 9 |
'------------------'------------------'------------------' |
Edited to add a missed elimination, marked by "#".
Last edited by wapati on Fri Jun 12, 2009 11:15 pm; edited 1 time in total |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Fri Jun 12, 2009 11:09 pm Post subject: |
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| arkietech wrote: | Danny,
I have learned something today. Still working on what it is.
I have yet to figure out whether either minimal or symmetrical are needed to make a good puzzle. I have got a lot to learn. |
Most symmetricals that are not minimal remain just as easy after being made minimal.
This puzzle was an exception in both areas, difficult before and still symmetrical and harder after.
Very unusual and cool. |
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daj95376
Joined: 23 Aug 2008
Posts: 3854
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| Posted: Sat Jun 13, 2009 3:12 am Post subject: |
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Everyone: First, I'd like to apologize for failing to make it clear that the elimination of a given increases the difficulty level radically in this puzzle.
| wapati wrote: | | daj95376 wrote: |
I can't find wapati's Sashimi Swordfish on <3> after the URs, but there's a finned Franken Jellyfish on <8> if anyone wishes to look for it. |
Well, this one woke us up, well done daj!
| Code: | .------------------.------------------.------------------.
|*3489 6 *389 | 1 2 7 | 89 489 5 |
| 789 5 1 | 34 48 389 | 2 789 6 |
| 489 789 2 | 5 6 89 | 3 149 1478 |
:------------------+------------------+------------------:
| 5 348 7 | 6 1 2 | 89 3489 48 |
| 2 348 6 | 9 5 38 | 7 1348 148 |
| 1 89#3 *389 | 7 *38 4 | 5 6 2 |
:------------------+------------------+------------------:
| 79 2 4 | 8 79 6 | 1 5 3 |
|*389 789-3 5 | 34 49 1 | 6 2 78 |
| 6 1 *38 | 2 *37 5 | 4 78 9 |
'------------------'------------------'------------------' |
Edited to add a missed elimination, marked by "#". |
I was afraid that you were attempting an elimination in [r8c2]. Unfortunately, this isn't a valid fish ... and the elimination was just lucky coincidence.
Your base set is "c135" and your cover set is "r169", with fin cell [r8c1]. However, the fin cell can only force eliminations that it sees in the cover set that aren't in the base set, of which only [r9c2]<>3 would qualify. |
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wapati
Joined: 10 Jun 2008
Posts: 472
Location: Brampton, Ontario, Canada.
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| Posted: Sat Jun 13, 2009 10:19 am Post subject: |
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| Yep, I messed up on the swordfish. Thanks Danny! |
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