## Empty Boxes - I

Everything about Sudoku that doesn't fit in one of the other sections
udosuk wrote:
Red Ed wrote:Yes, it's just a long chain of naked singles.

r8c6-r8c2-r5c2-r4c1-r1c1-r3c3-r3c6-r1c4-r1c9-r2c7-r4c7-r5c9-r7c9-r9c8-r9c3-r7c3
Then it's a matter of proving an empty box is determined by 8 filled box...
(E.g. there is no possible deadly pattern left...)

Correct for the first part of the proof.
You should easily solve the second part if you read carefully this thread (Thanks to Red Ed).

JPF
JPF
2017 Supporter

Posts: 3755
Joined: 06 December 2005
Location: Paris, France

### Three boxes just around the corner?

Code: Select all
`. . 1 . . 4 . . 6. 2 8 9 . . 4 . .7 . 3 . . . . 5 .. . . . 7 5 2 . .. . . . 3 . . . .. . . 1 . 8 . 3 .. . . . . . 7 6 5. . . . . . . 8 .1 . . . . . . . 9`

Can somebody eliminate the 1 in r9c1?

With best wishes

Claudia
claudiarabia

Posts: 288
Joined: 14 May 2006

It's impossible.
This pattern
Code: Select all
` x x x | x x x | x x x x x x | x x x | x x x x x x | x x x | x x x-------+-------+------- . . . | x x x | x x x . . . | x x x | x x x . . . | x x x | x x x-------+-------+------- . . . | . . . | x x x . . . | . . . | x x x . . . | . . . | x x x`

doesn't have any valid puzzle.
Any puzzle with this pattern has at least 2 solutions.

see :
http://forum.enjoysudoku.com/viewtopic.php?p=17488#p17488
http://forum.enjoysudoku.com/viewtopic.php?p=30961#p30961

JPF
JPF
2017 Supporter

Posts: 3755
Joined: 06 December 2005
Location: Paris, France

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