## Beyond Simple Sudoku Technique Set 2 - URT3?

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

### Beyond Simple Sudoku Technique Set 2 - URT3?

Since my previous post, I have read up on Unique Rectangles, but I am not sure if I have understood URT3 completely. I have a question, that has to do with Unqie Rectangle Type 3. Staring out with this puzzle:
Code: Select all
`*---+---+---*|...|...|...||...|841|...||.64|...|53.||---+---+---||..2|7.3|6..||7..|...|..5||.9.|.2.|.7.||---+---+---||..1|...|3..||.4.|.7.|.6.||9..|.8.|..7|*---+---+---*`

I get to the follwoing point using basic techniques:

Code: Select all
`*------------------+--------------------+-------------------*| 128   128   #79   | 56    3      56   | #14789 1489  1489 || 35    35    #79   | 8     4      1    | #279   29    6    || 18    6      4    | 2     9      7    |  5     3     18   ||-------------------+-------------------+-------------------|| 1458  158    2    | 7     15     3    |  6     1489  1489 || 7     138    368  | 469   16     4689 |  1248  1248  5    || 14568 9      568  | 456   2      458  |  148   7     3    ||-------------------+-------------------+-------------------|| 2568  7      1    | 4569  56     24569|  3     4589  2489 || 2358  4      358  | 13    7      259  |  189   6     1289 || 9     235    356  | 13    8      2456 |  14    145   7    |*-------------------+-------------------+-------------------*`

At this point I could use Unique Rectangle 4 to eliminate the 9s in r1c7 and r2c7.

Q) Am I correct in assuming that I could also remove <1,8> from r8c7 based on URT3 with naked quad?

Regards

_Skjalg
skjalg

Posts: 7
Joined: 21 October 2008

Yes.

R12 c7, because of the UR, are part of the quad that you noted.
wintder

Posts: 297
Joined: 24 April 2007

### Confirmation

OK. Thanks for the confirmation.
skjalg

Posts: 7
Joined: 21 October 2008

skjalg
Am I correct in assuming that I could also remove <1,8> from r8c7 based on URT3 with naked quad?

Or more simply, the elimination of the 9s in r12c7 automatically places 9 in r8c7, so eliminating <1,8>.
aran

Posts: 334
Joined: 02 March 2007