## Unique Pair

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

### Unique Pair

103427068408053270702080034915768423234500786876342005620875340340206857587034602

UniquePr.png (15.77 KiB) Viewed 205 times

Here we have 59 in r1c27 and it's easy enough to see that r3c27 cannot BOTH be reduced to 59 only if we are to have a uniqe solution.
But how does the logic prove that NEITHER of r3c7 can be 9?
Yogi
2017 Supporter

Posts: 176
Joined: 05 December 2015
Location: New Zealand

### Re: Unique Pair

C4R9C8b6c7 digit 1 => r3c6 <>1

Pretty easy to spot one of many fish/coloring options .(not on my cpu to post the fish logic atm)

What you ask for is uniqueness assumptive logic of a unique rectangle probably type 4 if i recall correctly

edit: yup type 4

due to the strong link in row 3 for digit 5
see elevens notes below.
Last edited by StrmCkr on Mon Mar 30, 2020 6:58 am, edited 1 time in total.
Some do, some teach, the rest look it up.

StrmCkr

Posts: 1163
Joined: 05 September 2006

### Unique Pair

Thanx. It's true that fish can be found to solve this puzzle. For example the Skyscraper {1r29} => 9r7c9 stte.
I just thought it would have been easier to understand a more direct causal connection between the 59 Locked Pair and the elimination of the corresponding 9s in Row3
Yogi
2017 Supporter

Posts: 176
Joined: 05 December 2015
Location: New Zealand

### Re: Unique Pair

Withdrawn - eleven is right (as usual) .

Leren
Last edited by Leren on Sat Mar 28, 2020 7:34 pm, edited 2 times in total.
Leren

Posts: 3915
Joined: 03 June 2012

### Re: Unique Pair

Yogi wrote:Here we have 59 in r1c27 and it's easy enough to see that r3c27 cannot BOTH be reduced to 59 only if we are to have a uniqe solution.
But how does the logic prove that NEITHER of r3c7 can be 9?

It is called unique rectangle type 4.
You have a strong link for 5 between the UR cells in row 3, so one must be 5 and both must not be 9 to prevent the deadly pattern 5-9-5-9.
eleven

Posts: 2461
Joined: 10 February 2008

### Re: Unique Pair

Gotcha. Thanx.
Yogi
2017 Supporter

Posts: 176
Joined: 05 December 2015
Location: New Zealand