10 Jan 07 X-treme

Welcome to the world of the unknown. Each day you need to solve <a href="http://www.sudocue.net/xfile.php">two mysteries</a>.<br>Take the X-R-Size or solve the X-Treme problem. Stuck? Found a nice solution? Tell us about it.
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sudokuEd
Grandmaster
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Joined: Mon Jun 19, 2006 11:06 am
Location: Sydney Australia

10 Jan 07 X-treme

Post by sudokuEd »

Found this X-treme very challenging. SudoCue rates it as "unfair 5289". Seems like we are getting one of these 5000's/week :D

Got stuck here but then found some really fun moves.

Code: Select all

.------------------.------------------.------------------.
| 58    46    589  | 568   7     4589 | 3     2     1    |
| 1     46    289  | 3     2489  2689 | 49    5     7    |
| 3     7     25   | 245   2459  1    | 69    68    489  |
&#58;------------------+------------------+------------------&#58;
| 58    239   7    | 1     24589 69   | 245   68    3489 |
| 4     29    1    | 2568  3     2589 | 2589  7     689  |
| 6     239   58   | 7     24589 2458 | 24589 1     389  |
&#58;------------------+------------------+------------------&#58;
| 9     1     4    | 258   6     258  | 7     3     25   |
| 7     8     6    | 245   245   3    | 1     9     25   |
| 2     5     3    | 9     1     7    | 68    4     68   |
'------------------'------------------'------------------'
Dont know what you call this move.
5 in r1c1 -> 8 in D\ must be in r6c6 or r9c9 ->(cross-over) -> 8 cannot be in r6c9
5 in r4c1 -> 8 in r6c3 -> no 8 in r6c9
-> no 8 in r6c9

Another one - this is the one that unlocks the puzzle.
5 in r1c1 -> 8 in r4c1 -> 6 in r4c8 -> no 6 in r5c9
5 in r4c1 -> 8 in r1c1 -> 6 in r9c9 -> no 6 in r5c9
-> no 6 in r5c9
-> r9c9 = 6 etc

Maybe Para can find another simpler way and teach me something else new. Thanks for showing us that move for the Dec 22 X-treme Para :D
Para
Yokozuna
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Posts: 384
Joined: Wed Nov 08, 2006 7:42 pm
Location: The Netherlands

Post by Para »

Code: Select all

.------------------.------------------.------------------. 
| 58    46    589  | 568   7     4589 | 3     2     1    | 
| 1     46    289  | 3     2489  2689 | 49    5     7    | 
| 3     7     25   | 245   2459  1    | 69    68    489  | 
&#58;------------------+------------------+------------------&#58; 
| 58    239   7    | 1     24589 69   | 245   68    3489 | 
| 4     29    1    | 2568  3     2589 | 2589  7     689  | 
| 6     239   58   | 7     24589 2458 | 24589 1     389  | 
&#58;------------------+------------------+------------------&#58; 
| 9     1     4    | 258   6     258  | 7     3     25   | 
| 7     8     6    | 245   245   3    | 1     9     25   | 
| 2     5     3    | 9     1     7    | 68    4     68   | 
'------------------'------------------'------------------'
I worked with the 6's.
R4C8 and R9C7 can't both be 6. This would leave no place for a 6 in N3 (or R3 take you pick :p). An 8 in a square they both see would force a 6 in both squares. So the 8 can be eliminated from all squares that they both see. Thus eliminating the 8 from R56C7. And this gives you a single 8 in C7. And from there it's just smooth sailing.

Para
Para
Yokozuna
Yokozuna
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Joined: Wed Nov 08, 2006 7:42 pm
Location: The Netherlands

Post by Para »

Learned myself something new by that move. Thought it would just be a one time thing Used it in yesterdays Nightmare as well. It's just so easy to check for.
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