Everything about Sudoku that doesn't fit in one of the other sections

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`+---+---+---+|...|347|...||2..|..6|4.7||.74|.28|..5|+---+---+---+|..3|4.1|..2||429|.63|8.1||7..|2.9|3..|+---+---+---+|5..|6.2|.1.||1.2|.35|..9||...|.14|...|+---+---+---+`

The next number should be (4 or 6) in R6C8 or R6C9. Please help with the logic.
LBJOHN

Posts: 3
Joined: 15 December 2005

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` *------------------------------------------------------------------------* | 689     15689   1568    | 3     4       7    | 1269    2689    68      | | 2       13589   158     | 159   59      6    | 4       389     7       | | 369     7       4       | 19    2       8    | 169     369     5       | |-------------------------+--------------------+-------------------------| | 68      568     3       | 4     578     1    | 5679    5679    2       | | 4       2       9       | 57    6       3    | 8       57      1       | | 7       1568    1568    | 2     58      9    | 3       456     46      | |-------------------------+--------------------+-------------------------| | 5       3489    78      | 6     789     2    | 7       1       348     | | 1       468     2       | 78    3       5    | 67      4678    9       | | 3689    3689    678     | 789   1       4    | 2567    235678  368     | *------------------------------------------------------------------------*`

Actually your next number would be the naked single in box 9 (a cell where only one number can go - it's actually shown above, but missing in your grid)

That leads you to a number of other naked singles, and eventually you'll be able to place a 6 in r6c9. A couple of moves before that you might notice that the 4 in r6c8 becomes a hidden single (only cell in that column that can contain that number).
Shazbot

Posts: 220
Joined: 24 September 2005