## TNU

Advanced methods and approaches for solving Sudoku puzzles

### TNU

There is a very easy but powerful new technique (at least I hope it's new, please correct me if I am wrong). Every grid consists of 54 units of three numbers, 27 vertically and 27 horizontally. Look at the following grid, and you will see what I mean.

*-----------*
|532|168|794|
|497|352|186|
|186|974|532|
|---+---+---|
|975|216|843|
|843|795|621|
|261|483|975|
|---+---+---|
|359|821|467|
|628|547|319|
|714|639|258|
*-----------*

The first horizontal "three numbers units" (TNU's) are <532>, <168> and <794>, the first vertical TNU's are <541>, <982> and <367>. Since in no grid there are two identical TNU's you can easily deduct from the solved TNU's in your grid which of the candidates are not possible. Example:
Code: Select all

*-----------------------------------------------------------*
| 2     1     9     | 8     27    5     | 6     4     3     |
| 8     7     6     | 1     4     3     | 2     9     5     |
| 25    4     3     | 6     2     9     | 1     8     7     |
|-------------------+-------------------+-------------------|
| 4567  56    45    | 3     1     46    | 9     2     8     |
| 456   3     2     | 45    9     468   | 7     1     46    |
| 1     9     48    | 7     68    2     | 5     3     46    |
|-------------------+-------------------+-------------------|
| 459   25    145   | 2459  3     7     | 8     6     129   |
| 3     256   7     | 259   568   68    | 4     5     129   |
| 4569  8     45    | 2459  56    1     | 3     57    29    |
*-----------------------------------------------------------*

As you see in C9R123 there is a TNU <357>, and in R8C123 you have a <3?7> combination. That means R8C2 <> 5.

Best wishes from Berlin

Neunmalneun

Neunmalneun

Posts: 52
Joined: 22 December 2005

Not quite but perhaps has a place !

Code: Select all
+---+---+---+
|...|...|..1|
|...|...|..2|
|...|...|..3|
+---+---+---+
|...|...|..4|
|...|...|..5|
|...|...|..6|
+---+---+---+
|...|...|...|
|...|...|...|
|123|4..|...|
+---+---+---+

r9c56 - cant be 5 or 6.

there is a hidden quad in r78c78

C
coloin

Posts: 1661
Joined: 05 May 2005

Uh, r8c2<>5 because r8c8=5.
Hidden Text: Show
Once upon a time I was a teenager who was active on here 2007-2011
999_Springs

Posts: 367
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

### Re: TNU

Neunmalneun wrote:Since in no grid there are two identical TNU's ...
Your post was too early, should have been dated April 1st (which it was in Germany, i suppose)
In your first grid there are some identical horizontal TNU's (like 532, 186, 843), in the second one you will have 219 both in r1c123 and r789c9 etc.

Added: Is this a server problem ?
The time now is Wed Apr 01, 2009 5:27 am, but i have Thu Apr 2 10:05:58 UTC 2009
eleven

Posts: 1657
Joined: 10 February 2008

### Re: TNU

eleven wrote:
Neunmalneun wrote:Since in no grid there are two identical TNU's ...
Your post was too early, should have been dated April 1st (which it was in Germany, i suppose)
In your first grid there are some identical horizontal TNU's (like 532, 186, 843), in the second one you will have 219 both in r1c123 and r789c9 etc.

Added: Is this a server problem ?
The time now is Wed Apr 01, 2009 5:27 am, but i have Thu Apr 2 10:05:58 UTC 2009

the forum clock slips by a noticable amount each day
the patterns game referee keeps track of it
anyone care to try notifying the admin(s)?
I've given up
www.ntp.org should be in that notice
and, even though the forum says so, this is not an april fools post
gsf
2014 Supporter

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

gsf wrote:its currently about 28h31m slow

Really? It only seems to me to be about 20h32m slow, after adjusting for daylight savings and all that rubbish...
Hidden Text: Show
Once upon a time I was a teenager who was active on here 2007-2011
999_Springs

Posts: 367
Joined: 27 January 2007
Location: In the toilet, flushing down springs, one by one.

### slow

gsf wrote:the forum clock slips by a noticable amount each day

currently circa 20 hr 35 min slow

Pat

Posts: 3460
Joined: 18 July 2005

### Re: slow

Pat wrote:
gsf wrote:the forum clock slips by a noticable amount each day

currently circa 20 hr 35 min slow

sorry, the number I gave was the offset from the default forum tz (gmt-0800) to gmt, so it was 8 hours off
thanks
gsf
2014 Supporter

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

but 999_Springs beat me by 6 minutes
( and i was so distracted i didn't even notice my comment was no longer necessary )

Pat

Posts: 3460
Joined: 18 July 2005

Well I have to admit that my concept is complete nonsense. And I have also to admit that I was too stupid to post it on time (at least it was April 1 here then). Next year I will do better.
Neunmalneun

Posts: 52
Joined: 22 December 2005