## Help! From Sunday Hard #2

All about puzzles in newspapers, magazines, and books

### Help! From Sunday Hard #2

This is as far as I have been able to get without guessing:

x7x x2x x16
1x6 x9x 2xx
xx2 461 xxx

721 x8x 634
xxx 214 xxx
594 x3x 128

2x7 853 xx1
xx9 14x 5xx
x15 x7x x8x

I guessed and was able to solve it, but I would like to know how to solve it without having to guess.

thanks!
helpless

Posts: 3
Joined: 19 April 2006

Row 1, has a hidden double (or a naked triple)....

but then why go for those when you have an x-wing (actually 2 of them that result in the same elimination)....the x-wing is formed from the candidate 4

tarek

tarek

Posts: 2917
Joined: 05 January 2006

Tarek,

thanks for your quick answer, but i must admit i don't have a clue as to what you are talking about. I reread the how to solve link, and looked at the FAQ, but couldn't find the answer in either place.

would you mind explaining it to me? thanks!
helpless

Posts: 3
Joined: 19 April 2006

helpless,

what techniques in solving sudoku to you use?

tarek

tarek

Posts: 2917
Joined: 05 January 2006

I haven't really learned the offical names, i just started doing them in my paper, and this is the first one i have had trouble with. I understand all of the tips from "how to solve" on sudoku.com, but haven't gotten much futher then that. thanks!
helpless

Posts: 3
Joined: 19 April 2006

Sorry helpless but I'm short of time for an explanation as they're closing down where I'm right now....

Hopefully some other member or when I have time this evening..I could elaborate a bit more...

tarek

tarek

Posts: 2917
Joined: 05 January 2006

back again halpless,

Well you need to master the following techniques.....some of which you may been using without even noticing............

1. Naked Singles
2. Hidden sigles
3. box-line interaction (aka locked candidates)
4. locked sets (naked & hidden doubles, triples,....)
5. X-wing

All of these can be found through links in the Collection of solving techniques thread....

Some simplified examples of each can be found also in the benchmark sudoku list....

Also some external links that everybody seems to find helpful can be found by searching for for the "Sudoku Susser" or "Sadman sudoku".

All the above techniques are weel documented & will be better explained then any of my attempts to explain them...

A bit of homework for you helpless....

take care

tarek

tarek

Posts: 2917
Joined: 05 January 2006

### Help! From Sunday Hard#2

tarek wrote:"..Hopefully some other member or when I have time this evening..I could elaborate a bit more..."

Hi Helpless,
The following links are popular for explaining solving techniques - just click on them:
http://www.angusj.com/sudoku/hints.php
http://www.simes.clara.co.uk/programs/sudokutechniques.htm
http://www.scanraid.com/BasicStrategies.htm