dailysudoku.com :: View topic - Susume's jellyfish trick

dailysudoku.com
Discussion of Daily Sudoku puzzles

FAQ

Memberlist

Usergroups

Profile

Susume's jellyfish trick

dailysudoku.com Forum Index -> Other puzzles

View previous topic :: View next topic

Author

Message

ravel

Joined: 21 Apr 2006
Posts: 536

Posted: Mon Nov 03, 2008 2:04 pm Post subject: Susume's jellyfish trick

In the thread A Pure Jellyfish Collection on the Players forum susume noticed (some posts down), that in puzzles, where 16 numbers are given in a 4x4 jellyfish pattern, it can be easy to find a jellyfish without pencilmarks.

Since the pattern of the current game (0058) of the Patterns Game has this property, you can find new examples there, e.g.

Code:

+-------+-------+-------+
| . . 5 | . . . | 8 . . |
| . 1 . | 4 . 5 | . 6 . |
| 7 . . | . . . | . . 1 |
+-------+-------+-------+
| . 5 . | 9 . 6 | . 2 . |
| . . . | . . . | . . . |
| . 6 . | 1 . 2 | . 4 . |
+-------+-------+-------+
| 4 . . | . . . | . . 9 |
| . 2 . | 6 . 9 | . 1 . |
| . . 1 | . . . | 3 . . |
+-------+-------+-------+ Tarek

There are givens in r2468c2468, but 378 is missing there.
With the 3 in r9c7 for these columns 2468 only rows 1357 remain, which can have a 3. So there must be a jellyfish (or something simpler) there for number 3. (The same holds for rows 2468, where 3 is restricted to columns 1359, giving the same eliminations)

Similar for 7 and 8.
This means, that the cells marked x cannot have 378.

Code:

+-------+-------+-------+
| x . 5 | . x . | 8 . x |
| . 1 . | 4 . 5 | . 6 . |
| 7 . x | . x . | x . 1 |
+-------+-------+-------+
| x 5 x | 9 x 6 | x 2 x |
| . . . | . . . | . . . |
| x 6 x | 1 x 2 | x 4 x |
+-------+-------+-------+
| 4 . x | . x . | x . 9 |
| . 2 . | 6 . 9 | . 1 . |
| x . 1 | . x . | 3 . x |
+-------+-------+-------+

Then in r7c3 6 remains as a naked single and the puzzle is solved.

In the same way this puzzle can be solved (here the jellyfish leave a naked pair):

Code:

+-------+-------+-------+
| . . 1 | . . . | 2 . . |
| . 3 . | 4 . 5 | . 6 . |
| 6 . . | . . . | . . 4 |
+-------+-------+-------+
| . 5 . | 6 . 2 | . 7 . |
| . . . | . . . | . . . |
| . 2 . | 7 . 3 | . 4 . |
+-------+-------+-------+
| 8 . . | . . . | . . 9 |
| . 6 . | 2 . 7 | . 3 . |
| . . 3 | . . . | 6 . . |
+-------+-------+-------+ JPF

Display posts from previous:

	dailysudoku.com Forum Index -> Other puzzles	All times are GMT
Page 1 of 1

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum