## Forcing chain for beginners

Advanced methods and approaches for solving Sudoku puzzles

### Forcing chain for beginners

I'm starting to learn advanced technique.I'd like to ask how can we recognise whether we can use forcing chain or not and how to identify which cell to start and end??
Kent

Posts: 98
Joined: 28 February 2006

Kent, you might try searching and reading the forum more rather than simply asking. You're holding a dictionary and asking how to spell crysanthimum, er, crisantimum, uh... posey.

First, Mike Barker went to great effort to make a nice post that links to lots of good stuff here.

Second, to search the forum, you can use the search command at the top of the page, however, a more useful search can be done by going to GOOGLE, clicking on ADVANCED SEARCH, type in SUDOKU.COM in the DOMAIN area of the form and FORCING CHAINS in the EXACT PHRASE area. Click here to see these results.

There is no royal road. No one can tell you where to look for this or any other tactic -- nor is there anyway of knowing if a tactic will help in a particular position without testing -- regardless if you're talking about naked pairs or complex, comprehensive forcing chains. We can describe *what* the patterns are -- but *how* could I tell you how to find a hidden triple?

Kent: "Where are my keys?"

Player's Forum: "I found them under the couch."

Kent "Could you explain to me how to find my keys in the future and how to know to look for them under the couch?"
tso

Posts: 798
Joined: 22 June 2005

They do explain what is forcing chain but i'm just curious how u choose the cell to start with.I did try on my own before i post it but everytime it didn;'t work.Thats why i posted here.
Kent

Posts: 98
Joined: 28 February 2006

I think that the question of how to start a forcing chain is one that bothers a lot of people, more so than looking for other patterns, although in essence it's really no different.

I look at the grid to see what I can see. I look for all other patterns first then if I'm stuck I take a promising looking bivalue cell and start a chain and see where it goes. I don't think I can explain what is 'promising' - except that I'm hoping that the more puzzles I do the more likely I am to pick a useful starting place.

If you want a systematic approach then tso has already written this about one way of finding chains - you might like to try that.
emm

Posts: 987
Joined: 02 July 2005

Thanks a lot em.You've helped my a lot.Really appreaciate it
Kent

Posts: 98
Joined: 28 February 2006

### Re: Forcing chain for beginners

Kent wrote:I'm starting to learn advanced technique.I'd like to ask how can we recognise whether we can use forcing chain or not and how to identify which cell to start and end??

Hi Kent, Here is a thread that you should take a look. It contains methods on how forcing chains can be identified by some of the players.
Jeff

Posts: 708
Joined: 01 August 2005

Thanks a lot Jeff!!!
Kent

Posts: 98
Joined: 28 February 2006