Strategy for this pattern?

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

Strategy for this pattern?

Postby luxturna » Mon Jan 08, 2018 2:38 am

(Looking at top row and middle-right square in example below)
Image

In the top row, 3 and 7 are an option for each cell, but 1 is in only two of them. Is there a technique for narrowing this down? Another example of this is the 3 and 8 and then the 1 in the middle-right section.

Also, are there any recommended strategies I could try using here? I've been looking, but I can't notice any. I haven't done much with puzzles like this, so I haven't needed to try any "advanced" strategies, but I'm really struggling now. :?
luxturna
 
Posts: 1
Joined: 08 January 2018

Re: Strategy for this pattern?

Postby m_b_metcalf » Mon Jan 08, 2018 2:36 pm

luxturna wrote:In the top row, 3 and 7 are an option for each cell, but 1 is in only two of them. Is there a technique for narrowing this down? Another example of this is the 3 and 8 and then the 1 in the middle-right section.

Also, are there any recommended strategies I could try using here? I've been looking, but I can't notice any. I haven't done much with puzzles like this, so I haven't needed to try any "advanced" strategies, but I'm really struggling now. :?

The answer to your first question is 'no'. However, take a close look at column 7. It contains a 'naked pair': the two values 1 and 3 appear together in two cells and so, regardless of which contains the 1 and which the 3, neither of these two values can appear anywhere else in that column. Meaning that r6c7 can only be 8.

HTH

Mike Metcalf
User avatar
m_b_metcalf
2017 Supporter
 
Posts: 8918
Joined: 15 May 2006
Location: Berlin

Re: Strategy for this pattern?

Postby Leren » Mon Jan 08, 2018 7:47 pm

You can also take a look at Row 6. The cells in Columns 1, 7 & 9 contain only three different digits 1, 3 & 8, so they must eventually appear there.

So they can't appear elsewhere in Row 6. In particular r6c3 can't be 3, so it's 7. That's a naked triple move.

If you are unfamiliar with naked pair, triple and quad moves you can find a good write-up here.

Leren

<edit>

Just checked your puzzle and it solves in singles from your solved cell status. For other solvers the line format is here : 85..264.99.6..5......891..6568913247...687.95...254.6.685.79....195..6...3416.9..

The first single is 1 in Row 1 Column 3. It's the only 1 in Box 1. Also Row 6 Column 2 must be 9 because it's the only 9 in Column 2 (and Box 4).

Also there's only one 5 in Column 7, in Row 3. And there is one 5 in Row 9, in Column 8 (It's also the only 5 in Box 9).

Making appropriate mark-offs and proceeding in this way you can solve the puzzle with a cascade of singles. So much for naked tuples - Duh :D

Leren
Leren
 
Posts: 3210
Joined: 03 June 2012


Return to Help with puzzles and solving techniques