## curious puzzle

Post the puzzle or solving technique that's causing you trouble and someone will help

### curious puzzle

according to my solver this puzzle has one solution:
Code: Select all
`...|...|....4.|2.1|.6...8|.7.|9..-----------.8.|...|.5...5|...|8...6.|...|.4.-----------..9|.8.|5...1.|6.4|.2....|...|...`

but as you solve it you reach a point where R2C3=R2C7=R8C3=R8C7=(3 or 7). Now according to UR this would lead to 2 solutions. So I put the puzzle into P.J.Downey's program and it only finds one solution too. What's going on??
ab

Posts: 451
Joined: 06 September 2005

### Re: curious puzzle

ab wrote:but as you solve it you reach a point where R2C3=R2C7=R8C3=R8C7=(3 or 7). Now according to UR this would lead to 2 solutions. So I put the puzzle into P.J.Downey's program and it only finds one solution too. What's going on??

can you provide a pencimark grid showing the point in question?
 well duh the opening grid has it
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`1235679  23579   12367  | 34589   34569   35689  | 12347    1378  1234578  3579     4       37   |   2      359      1    |   37      6      3578 12356    235      8    |  345      7      356   |   9       13    12345------------------------+------------------------+------------------------ 123479    8     12347  | 13479   123469  23679  | 12367     5     123679 123479   2379     5    | 13479   123469  23679  |   8      1379   123679 12379     6      1237  | 135789  12359   235789 |  1237     4     12379------------------------+------------------------+------------------------ 23467    237      9    |  137      8      237   |   5      137    13467  3578     1       37   |   6      359      4    |   37      2      37892345678   2357   23467  | 13579   12359   23579  | 13467   13789  1346789`

and it can be advanced to this point
Code: Select all
`12367   9    126  | 3458   46   3568 | 124   137   1245  5     4     37  |  2     9     1   |  37    6     8 1236   3     8   | 345    7    356  |  9     13   1245------------------+------------------+------------------ 1234   8    124  | 479   146   2679 | 126    5    1236 1234   7     5   |  4    146    26  |  8     9    1236  9     6     12  |  58    3     58  |  12    4     7------------------+------------------+------------------  46    2     9   |  1     8     37  |  5     37    46  8     1     37  |  6     5     4   |  37    2     9 3467   5     46  | 379    2    379  | 146    8    146`
gsf
2014 Supporter

Posts: 7306
Joined: 21 September 2005
Location: NJ USA

### Re: curious puzzle

ab wrote:but as you solve it you reach a point where R2C3=R2C7=R8C3=R8C7=(3 or 7). Now according to UR this would lead to 2 solutions. So I put the puzzle into P.J.Downey's program and it only finds one solution too. What's going on??

The 4 cells you list do not form a unique rectangle. Unique rectangles must lie in exactly 2 rows, 2 columns and 2 blocks.
re'born

Posts: 551
Joined: 31 May 2007