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kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

I have never been very successfull locating swordfish. I think I have read most commonly available threads on this subject. For some reason, I have not been able to reduce the definitions to a visual search algorithm. I visit Brainbashers frequently and many of their superhard puzzles contain swordfish, forcing me to peak at the step by step solution. I would appreciate any help you folks can offer.

kuskey

daj95376 · Joined: 23 Aug 2008 Posts: 3854

Besides Size, fish are also classified by their Shape.

kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

That is a good question because I never associated size and shape as a pair. Initially its basic swordfish growing to Franken, and others perhaps. I have come across the terms you presented but never gave them much consideration. Some examples would help me if you would be so kind and exactly how would you logically search rows and columns to identify the pattern. The one I have not heard of is the 1-fish.

daj95376 · Joined: 23 Aug 2008 Posts: 3854

The 1-fish is there for "completeness". It's equivalent to a Hidden Single.

Describing how to find a "basic" Swordfish is relatively easy. However, they are, IMO, less common than "finned" and "Sashimi" Swordfish, which are more difficult to find. The remaining shapes get successively more difficult to find, IMO.

[Withdrawn: I'm not really prepared to provide examples.]

Marty R. · Posted: Sat Aug 20, 2011 12:21 am Post subject:

This is probably not the kind of input you're looking for, but I don't look; too much work for too little reward.

keith · Posted: Sat Aug 20, 2011 9:20 am Post subject:

kuskey,

A swordfish is three strong links in rows (columns) that line up in some way in columns (rows).

I'm with Marty - they are not worth looking for. If you understand X-wings and kites / skyscrapers / turbot fish, swordfish are unnecessary. (I am sure someone has a counterexample to that statement.)

Please post those BB puzzles that "require" a swordfish in the "Other Puzzles" forum. We'll see what other solution paths there are.

As for the "almost" swordfish, finned, kraken, sashimi, franken, ... they are basically useless (not findable) for those of us who solve puzzles manually, with pencil and paper.

Keith

kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

Thanks for the help. I agree with you all that trolling for fish is probably more work than its worth. Even X-wings can require a lot of time when the solved cells are minimal.

I will pass along any grids advertized to require swordfish so you can look at them. So far other techniques have solved the grids.

daj95376 · Joined: 23 Aug 2008 Posts: 3854

In another forum, Tarek is accumulating what he terms, "A Pure Swordfish Collection". (basic) Swordfish are the only advanced steps needed in his puzzles. They may not be easy to circumvent.

Tarek Puzzle #2:

Marty R. · Posted: Sun Aug 21, 2011 11:45 pm Post subject:

I tried monkeying around with this puzzle in Draw/Play and got this far with basics.

kuskey · Joined: 10 Dec 2008 Posts: 141 Location: Pembroke, NH

Marty, I agree with your after-basics code, which I found to be quite challenging. Will try to get the code into some type of solver that facilitates searching for fish one number at a time. Any suggestions here?

keith · Posted: Mon Aug 22, 2011 3:39 am Post subject:

The Swordfish is on 9 in R279. It makes eliminations in C348.

To be quite honest, I would never recognize it, and I am not bent on learning how.

Then, there is a similar swordfish on 8 that solves the puzzle.

Sudoku Susser is very good for "fishy patterns".

Keith

daj95376 · Joined: 23 Aug 2008 Posts: 3854

Marty R. · Posted: Mon Aug 22, 2011 3:34 pm Post subject:

What is the definition of an S-Wing? It looks like you used the same candidate to follow two different paths that reached the same conclusion.

daj95376 · Joined: 23 Aug 2008 Posts: 3854

Pat · Joined: 23 Feb 2010 Posts: 207

Pat · Joined: 23 Feb 2010 Posts: 207

Pat · Joined: 23 Feb 2010 Posts: 207

ffred · Joined: 29 Oct 2012 Posts: 19 Location: Kent, Egland

Marty & Keith, I'm glad I'm not the only person who dislikes complex swordfish patterns - I thought I was a bit wimpish. Soon after the sudoku craze started (04, 05?) I was given a book of puzzles but it was so riddled with swordfish (which I couldn't see without writing in candidates) that I just gave up on sudokus.

Still, any port in a storm as they say, and I do look for swordfish if all else fails. (But not variants, which I've never found.) I'm about to post a puzzle that I just couldn't unlock without a swordfish.