yeh!! These new sudoku's are ace the tricky ones are quite hard to get started, but once you get a couple in, they just fall into place

- AJ
**Posts:**1**Joined:**08 September 2005

Spa wrote:Go with your first thought...the order will work itself out as you go on, and then look at the cells immediately above and below that group of five.

yes, I went on to 6,1 for the 7 enclosure in box 2 and 1,7 for the 8 enclosure in box 8. Seemed to be going well for a while afterwards, but then ended up stuck when I came to box 9, when I had 3 and 7 left in column 7, which could not be placed in the 24 enclosure.

I'll have to start again sometime...

- possum
**Posts:**86**Joined:**05 April 2005

There is a solver here:

http://homepage3.nifty.com/funahashi/game/game676eng.html

I've tested it on two puzzles. It took only a 10 or 15 seconds to solve the one I previously posted before the TIMES started publishing them http://forum.enjoysudoku.com/viewtopic.php?t=995&postdays=0&postorder=asc&start=0, but it took many minutes to solve the "Deadly" one here: http://www.timesonline.co.uk/article/0,,7-1757275_2,00.html

And again -- this solver reported one and only one solution to each puzzle. The puzzle I posted has two other solutions if you ignore the "no duplicate digits in an enclosure" rule that the TIMES forgot to include in their article.

http://homepage3.nifty.com/funahashi/game/game676eng.html

I've tested it on two puzzles. It took only a 10 or 15 seconds to solve the one I previously posted before the TIMES started publishing them http://forum.enjoysudoku.com/viewtopic.php?t=995&postdays=0&postorder=asc&start=0, but it took many minutes to solve the "Deadly" one here: http://www.timesonline.co.uk/article/0,,7-1757275_2,00.html

And again -- this solver reported one and only one solution to each puzzle. The puzzle I posted has two other solutions if you ignore the "no duplicate digits in an enclosure" rule that the TIMES forgot to include in their article.

- tso
**Posts:**798**Joined:**22 June 2005

TSO - thanks for the pointer to the puzzle you'd previously posted. I was on holiday late August, so missed it. More of a stretch than the recent Times ones, mainly because there were far fewer pairs and triples.

The interesting thing for me was that I came across what may be a brand new technique that speeded things up for me - it's probably been discussed somewhere before, but I've not spotted it. It's what I'll call the MUSCLE technique - Malicious Uniqueness Short Cut Logical Extension.

I used it twice when solving it... this is one of the examples:

At one stage I had r9c1 and r9c2 as potential 7s and 9s given the 16 pair. In box 4 5 could go in either r5c2 or r6c2, the latter of which would have left a 7/9 pair in r5c1 and r5c2. I therefore deduced that 5 had to go in r5c2 as otherwise I would be left with 2 potential solutions given the 7s and 9s in rows 5 and 9 and columns 1 and 2 - hence the uniqueness shortcut.

Is this a valid technique ? It's certainly logical given the assertion that each puzzle only has one valid solution... just probably not the intended path to the unique solution.

Paul

The interesting thing for me was that I came across what may be a brand new technique that speeded things up for me - it's probably been discussed somewhere before, but I've not spotted it. It's what I'll call the MUSCLE technique - Malicious Uniqueness Short Cut Logical Extension.

I used it twice when solving it... this is one of the examples:

At one stage I had r9c1 and r9c2 as potential 7s and 9s given the 16 pair. In box 4 5 could go in either r5c2 or r6c2, the latter of which would have left a 7/9 pair in r5c1 and r5c2. I therefore deduced that 5 had to go in r5c2 as otherwise I would be left with 2 potential solutions given the 7s and 9s in rows 5 and 9 and columns 1 and 2 - hence the uniqueness shortcut.

Is this a valid technique ? It's certainly logical given the assertion that each puzzle only has one valid solution... just probably not the intended path to the unique solution.

Paul

- Enigma
**Posts:**53**Joined:**14 June 2005

Enigma wrote:MUSCLE technique - Malicious Uniqueness Short Cut Logical Extension.

Yes, of course it's valid. There has been disagreement on this issue -- but everyone else is wrong.

See: An Unmentioned Logic Technique .

- tso
**Posts:**798**Joined:**22 June 2005