The New Sudoku Players' Forum

[angusj]

hey come on guys ! its nice to have fun but what about a few 'straight' answers??

Hi goldie. Don't worry, Ocean has lost me too.

Regarding Turbot fish, it's a subset of simple colours. However, in fairness to Nick70 who named them, it's a fairly large subset. Use the "search" at the top of the page for more info about them.

Edit: As a good example of colours and turbot fish, have a look at my post here: http://www.setbb.com/phpbb/viewtopic.php?p=1532&mforum=sudoku#1532 . (The Puzzle 6 highlighted colors layout is a turbot fish pattern whereas Puzzle 4 is not.)

[stuartn]

I think what Ocean has shown is a pile of superimposed x-wings (on the rows)..... sseparate out the squares and see.......

stuartn

[Karyobin]

Just because a swordfish might be rare "in the wild", that is, in a puzzle generated at "random", doesn't mean that one cannot create unlimited puzzles that contain swordfish at will. For example Simple Sudoku's Extreme contain at least one Swordfish by design. I like finding Swordfish. Like it's name sake, you are right, you're not likely to find it at random anywhere you look -- but somehow, I manage to find a piece to grill for dinner least once a week.

Quite right, but I only tend to hunt in the wild. I always feel kind of depressed in fish farms.

Also, the methods that can be used to generate a puzzle at "random" are diverse enough to make many patterns as rare or common as one wishes. Furthermore, it seems obviou ... *ouch* ... what the heck did I just sit on ... wha? ... crud, I've got to clean these tesseracts out of this couch ... I gotta go, I think my hip is bleeding ... gol durn 4th dimension.

Steady on there tso, no-one's said "crud" since Judge Dredd. And that tesseract stuff, well I mean, I know I started it but there comes a time when one needs to sit quietly in a darkened room.

Oh well, better get back to writing the quiz now. Drok it.

[Ocean]

Sorry I mentioned the exotic exclusion patterns. Will eventually come back to them in a different forum - and only if they can be properly explained and analyzed.

[stuartn]

You mean they're not a pile of x-wings?

stuartn

[Ocean]

You mean they're not a pile of x-wings?

stuartn

Hi Stuart,

You are right in pointing out the connection to x-wings. The effect is quite similar or related. The design is also based on knowledge of x-wing type effect. Strangely enough it seems to be easier to design such patterns than to find them. They looked prospective as subject for research, but might as well turn out to be a dead end. Will come back to the subject if I manage to give a general description, occurance statistics, etc.

[GFox49]

Logic is all you should really need. Don't get hung up on terms like swordfish, xy-whatever, etc. First work each box of nine - writing in small numerals in each square what possibilities are. This will allow you to identify solo candidates in some of those boxes. then just begin to work the puzzle by row, and then again by column. You will find more "only possibilities". Remember to x-out same number in other boxes in each row/column when you find one of these candidates. Keep this up, logic and attrition will work every time. A true Suduko design will not require "guessing". It takes practice, but it does work!

[stuartn]

GFox49 - you're quite right - but to a certain limit. With more complex grids the logic required becomes more complex - hence the development of these rather odd 'fishy' techniques. You're walking a well trodden path.

stuartn

[Wolfgang]

Regarding Turbot fish, it's a subset of simple colours.

To be precise, only 2 of the 4 kinds of Turbot fish (cases 1 and 3), Nick70 (he seems to be gone ) described here are also simple colours cases (where weak sides are not handled).
BTW: Could someone improve the "Search" mechanism? You dont even find the threads with the search terms in the title, eg "Turbot fish"

[angusj]

To be precise, only 2 of the 4 kinds of Turbot fish (cases 1 and 3)

See recent discussion here:
http://www.sudoku.org.uk/discus/messages/6/202.html?1126524935#POST1600
http://www.setbb.com/phpbb/viewtopic.ph ... udoku#1643

[uncle_wong_hk]

Hi guys,

My opinion is to forget the advanced programming language for this kind of logic game.
You will be stucked in the debugging very easily.
The logic for Sudoku is quite straight forward.
Excel will be good enough for it.
I am not trying to solve the Sudoku fully automatically.
Or otherwise, VBA for Excel is necessary.
I just use the Excel to assist the game playing.

For this case, two times trial and error are required.
It took less than five minutes.

749 123 685
251 698 347
386 457 921

825 349 716
694 871 253
173 562 894

537 284 169
412 936 578
968 715 432

Uncle Wong.

[emm]

A different point of view is always refreshing - but I would like to point out that I have already told Uncle Wong that one can be too helpful, before anyone else gets stuck in.