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Impossible Menneske No. 02

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keith

Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

Posted: Tue Feb 26, 2013 11:38 pm Post subject: Impossible Menneske No. 02

Code:

M6912298 Impossible (5997)
+-------+-------+-------+
| . . . | . 8 . | 5 . 7 |
| . 6 . | . . . | . . . |
| 4 . . | 7 . . | . 1 . |
+-------+-------+-------+
| . . 1 | . . . | . 8 9 |
| . . . | . . 5 | 2 . . |
| 7 . . | . 9 . | 4 . . |
+-------+-------+-------+
| . . . | . . 6 | . . 4 |
| . . 2 | 1 . . | . 9 . |
| . . 6 | 5 . . | . . . |
+-------+-------+-------+

Play this puzzle online at the Daily Sudoku site

Ask, ye shall receive!

Keith

Last edited by keith on Sun Mar 17, 2013 4:29 am; edited 1 time in total

JC Van Hay

Joined: 13 Jun 2010
Posts: 494
Location: Charleroi, Belgium

Posted: Wed Feb 27, 2013 10:39 am Post subject:

#1. r56c9=1=r79c7, r5c3=4, r6c89=5=r4c12, r2c3=7
#2. Chain[2] : Finned XWing(6R16) : r1c8=r1c4-r6c4=r6c89 :=> -6r5c8

Strongest digits : 5,6,1 whose X Chains are weakly coupled in r23c5 and r6c89.
They enter the following loop :

Code:

+----------------------+---------------------------+-----------------------+
| 1239 1239 39 | 2349(6) 8 12349 | 5 234(6) 7 |
| 123589 6 7 | 2349 -234(15) 12349 | 389 234 238 |
| 4 23589 3589 | 7 -23(56) 239 | 3689 1 2368 |
+----------------------+---------------------------+-----------------------+
| 2356 235 1 | 2346 23467 2347 | 367 8 9 |
| 3689 389 4 | 368 367(1) 5 | 2 37 36(1) |
| 7 238 38 | 2368 9 1238 | 4 -3(56) -36(15) |
+----------------------+---------------------------+-----------------------+
| 13589 135789 3589 | 2389 237 6 | 1378 2357 4 |
| 358 34578 2 | 1 347 3478 | 3678 9 3568 |
| 1389 134789 6 | 5 2347 234789 | 1378 237 238 |
+----------------------+---------------------------+-----------------------+

Loop[6] : 6r1c4=(6-5)r3c5=(5-1)r2c5=1r5c5-1r5c9=(1-5)r6c9=(5-6)r6c8=6r1c8 @
:=> r3c5=56=r6c8,r2c5=15=r6c9

Adding the chain 5r3c3=5r7c3-5r7c8=5r6c8 to the loop solves the loop because
r6c9=5->no 5 in Box 2 :=> r6c8=5.
Interpretation :

Code:

+------------------------+--------------------------+--------------------+
| 1239 1239 39 | 2349(6) 8 12349 | 5 234(6) 7 |
| 123589 6 7 | 2349 12345 12349 | 389 234 238 |
| 4 23589 389(5) | 7 23-5(6) 239 | 3689 1 2368 |
+------------------------+--------------------------+--------------------+
| 2356 235 1 | 2346 23467 2347 | 367 8 9 |
| 3689 389 4 | 368 1367 5 | 2 37 136 |
| 7 238 38 | 2368 9 1238 | 4 3(56) 1356 |
+------------------------+--------------------------+--------------------+
| 13589 135789 389(5) | 2389 237 6 | 1378 237(5) 4 |
| 358 34578 2 | 1 347 3478 | 3678 9 3568 |
| 1389 134789 6 | 5 2347 234789 | 1378 237 238 |
+------------------------+--------------------------+--------------------+

#3. Chain[4] : 5r3c3=5r7c3-5r7c8=(5-6)r6c8=6r1c8-6r1c4=6r3c5 :=> -5r3c5; 18 Singles; r79c8=23 :=> r9c9=8
#4. Chain[2] : Skyscraper(8C36) : r7c3=r6c3-r6c6=r8c6 :=> -8r7c4.r8c12;ste

oaxen

Joined: 10 Jul 2006
Posts: 96

Posted: Fri Mar 01, 2013 6:17 pm Post subject:

This was the hardes puzzles I ever met. I solved it, but can´t remember the step I took. something like van hay anyhow.

DonM

Joined: 15 Sep 2009
Posts: 51

Posted: Fri Mar 01, 2013 9:10 pm Post subject:

oaxen wrote:

This was the hardes puzzles I ever met. I solved it, but can´t remember the step I took.

I hate when that happens. Smile

keith

Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

Posted: Fri Mar 01, 2013 10:32 pm Post subject:

DonM wrote:

oaxen wrote:

This was the hardes puzzles I ever met. I solved it, but can´t remember the step I took.

I hate when that happens. Smile

oaxen,

I said:

Quote:

Ask, ye shall receive!

Keith

DonM

Joined: 15 Sep 2009
Posts: 51

Posted: Fri Mar 01, 2013 10:55 pm Post subject:

Menneske Impossible 2 ssts ER=7.3

Code:

1. (5)r7c3=r3c3-r3c5=(5-1)r2c5=r5c5-r5c9=(1-5)r6c9=(5)r6c8 :=> -5r7c8 ->3 singles

Code:

*-----------------------------------------------------------------------------*
| 1239 1239 39 |*23469 8 12349 | 5 *2346 7 |
| 123589 6 7 | 2349 12345 12349 | 389 234 238 |
| 4 23589 3589 | 7 2356 239 | 389 1 2368 |
|-------------------------+-------------------------+-------------------------|
| 2356 235 1 |G2346 23467 2347 | 37 8 9 |
| 3689 389 4 |G368 137-6 5 | 2 *367 G136 |
| 7 238 38 |*2368 9 1238 | 4 5 *136 |
|-------------------------+-------------------------+-------------------------|
| 13589 135789 3589 | 2389 237 6 | 1378 237 4 |
| 38 3478 2 | 1 347 3478 | 6 9 5 |
| 1389 134789 6 | 5 2347 234789 | 1378 237 238 |
*-----------------------------------------------------------------------------*

2.(6)r45c4=[(6)BW:(6)r1c48,r5c8,r6c49]=(6)r5c9-r3c9=(6)r3c5 => -6r45c5 -> r3c5=6 => cascade of singles
-> np(89)r23c7 => r9c9=8 -> skyscraper(8)r5c4,r6c3,r7c34 => -8r6c6
stte

The core of step #2 of the solution is the BW or BrokenWing/Oddagon at (6)r1c48, r5c8, r6c49 (marked by *). This is a potential 5-sided loop of conjugate links of 6s which would be impossible if it existed by itelf. There are three 6s called 'Guardians' (marked by G above) at r4c45 and r5c9 that prevent that pattern. Thus, if guardian (6)r5c9 is not true then guardians (6)r45c4 must be true and vice-versa.

Of interest also: The BW pattern actually eliminates (6)r5c5 immediately because if it were true, it would eliminate all 3 guardians which can't happen. This is interesting because it is rare to find immediate BW eliminations in more complicated puzzles. BTW: Since the chain eliminates both 6s at r45c5 anyway, it isn't necessary to add this as a separate step.

(Keith, enjoyed these 2 puzzles-thanks!)

oaxen

Joined: 10 Jul 2006
Posts: 96

Posted: Sat Mar 02, 2013 3:59 pm Post subject:

Now I have recapitulated. Any of "ones" in block E gives correct five and six in block I. Next valuable bivalues are the "six" in block C. R1C8 leads to a complete puzzle.

arkietech

Joined: 31 Jul 2008
Posts: 1834
Location: Northwest Arkansas USA

Posted: Fri Mar 08, 2013 12:31 pm Post subject:

Code:

*-----------------------------------------------------------------------------*
| 1239 1239 39 | 23469 8 12349 | 5 2346 7 |
| 123589 6 7 | 2349 12345 12349 | 389 234 238 |
| 4 23589 3589 | 7 2356 239 | 3689 1 2368 |
|-------------------------+-------------------------+-------------------------|
| 2356 235 1 | 2346 23467 2347 | 367 8 9 |
| 3689 389 4 | 368 1367 5 | 2 367 136 |
| 7 238 38 | 2368 9 1238 | 4 356 1356 |
|-------------------------+-------------------------+-------------------------|
| 13589 135789 3589 | 2389 237 6 | 1378 2357 4 |
| 358 34578 2 | 1 347 3478 | 3678 9 3568 |
| 1389 134789 6 | 5 2347 234789 | 1378 237 238 |
*-----------------------------------------------------------------------------*
net
5r3c5 5r7c3 5r6c8 6r6c9 6r1c8
5r3c5 6r1c4
contradiction -5r3c5

*--------------------------------------------------------------------*
| 1239 139 39 | 2349 8 12349 | 5 6 7 |
| 12389 6 7 | 239 5 1239 | 89 4 23 |
| 4 389 5 | 7 6 239 | 89 1 23 |
|----------------------+----------------------+----------------------|
| 6 5 1 | 24 247 247 | 3 8 9 |
| 389 389 4 |f38 1 5 | 2 7 6 |
| 7 2 *38 | 6 9 3-8 | 4 5 1 |
|----------------------+----------------------+----------------------|
| 5 13789 *389 |*289 237 6 | 17 23 4 |
| 38 3478 2 | 1 347 478 | 6 9 5 |
| 139 13479 6 | 5 2347 2479 | 17 23 8 |
*--------------------------------------------------------------------*
Sashimi X-Wing
r67c34,fr5c4 => -8r6c6; ste

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