The New Sudoku Players' Forum

[daj95376]

Code: Select all

# here is the pattern and elimination
 *-----------------------------------------------------------*
 | .     .     3     | .     .     3     | 3     .     .     |
 | .     .     3     | 3     .     .     | 3     .     .     |
 | .     3     .     | .    -3     3     | 3     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .     .     | .     .     .     | .     .     3!    |
 | 3     .     .     | 3     .     .     | .     .     .     |
 | .     3     .     | 3     3     .     | .     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .     3     | .     3     .     | .     .     .     |
 | 3     3     3     | .     .     3     | .     .     .     |
 | .     .     .     | .     .     .     | .     3!    .     |
 *-----------------------------------------------------------*


Code: Select all

# a Sashimi Swordfish ???
 *-----------------------------------------------------------*
 | .     .    *3     | .     .    #3     |*3     .     .     |
 | .     .    *3     |#3     .     .     |*3     .     .     |
 | .     3     .     | .    -3     3     | 3     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .     .     | .     .     .     | .     .     3!    |
 | 3     .     .     | 3     .     .     | .     .     .     |
 | .     3     .     | 3     3     .     | .     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .    *3     | .    *3     .     | .     .     .     |
 | 3     3     3     | .     .     3     | .     .     .     |
 | .     .     .     | .     .     .     | .     3!    .     |
 *-----------------------------------------------------------*


[Ruud]

Correct, this one could have 4 candidates in the fin. Without the fin, the pattern degenerates, making it a true Sashimi.

Code: Select all

# a Sashimi Swordfish !!!
 *-----------------------------------------------------------*
 | .     .    *3     |(#)    .    #3     |*3     .     .     |
 | .     .    *3     |#3     .    (#)    |*3     .     .     |
 | .     3     .     | .    -3     3     | 3     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .     .     | .     .     .     | .     .     3!    |
 | 3     .     .     | 3     .     .     | .     .     .     |
 | .     3     .     | 3     3     .     | .     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .    *3     | .    *3     .     |(*)    .     .     |
 | 3     3     3     | .     .     3     | .     .     .     |
 | .     .     .     | .     .     .     | .     3!    .     |
 *-----------------------------------------------------------*


[daj95376]

Thanks Ruud for the verification and the additional information!!! I'm having trouble understanding some of the fish types. However, I keep hammering away as examples (appear to) present themselves.

===== ===== ===== ===== When I get really tired, I come up with ...

Having fun trying to express a Kraken (???) Swordfish as a contradiction chain. It only works because there's a single elimination. (I need to get some sleep!!!)

Code: Select all

 *-----------*
 |.45|2..|1..|
 |7..|34.|.9.|
 |..6|...|..7|
 |---+---+---|
 |...|6..|...|
 |8..|5.3|..6|
 |...|..4|...|
 |---+---+---|
 |4..|...|8..|
 |.5.|.32|..1|
 |..3|..1|67.|
 *-----------* # original


Code: Select all

# [r7c2]-2-(Swordfish [r467C358])=2=([r2c3]|[r3c8])-2-[r3c1]=2=[r9c1]-2-[r7c2]
 *---------------------------------------------------*
 | 39   4     5    | 2    7    89   | 1    6    38   |
 | 7    128  #128  | 3    4    6    | 25   9    258  |
 | 239  289   6    | 1    58   589  | 4   #23   7    |
 |-----------------+----------------+----------------|
 | 15   3     9    | 6   *12   78   | 257 *258  4    |
 | 8    27    4    | 5    9    3    | 27   1    6    |
 | 15   6    *27   | 78  *12   4    | 3   *258  9    |
 |-----------------+----------------+----------------|
 | 4    17-2 *12   | 9    6    57   | 8   *235  235  |
 | 6    5     78   | 78   3    2    | 9    4    1    |
 | 29   289   3    | 4    58   1    | 6    7    25   |
 *---------------------------------------------------*


[ronk]

Having fun trying to express a Kraken (???) Swordfish as a contradiction chain. It only works because there's a single elimination.

Code: Select all

# [r7c2]-2-(Swordfish [r467C358])=2=([r2c3]|[r3c8])-2-[r3c1]=2=[r9c1]-2-[r7c2]
 *---------------------------------------------------*
 | 39   4     5    | 2    7    89   | 1    6    38   |
 | 7    128  #128  | 3    4    6    | 25   9    258  |
 | 239  289   6    | 1    58   589  | 4   #23   7    |
 |-----------------+----------------+----------------|
 | 15   3     9    | 6   *12   78   | 257 *258  4    |
 | 8    27    4    | 5    9    3    | 27   1    6    |
 | 15   6    *27   | 78  *12   4    | 3   *258  9    |
 |-----------------+----------------+----------------|
 | 4    17-2 *12   | 9    6    57   | 8   *235  235  |
 | 6    5     78   | 78   3    2    | 9    4    1    |
 | 29   289   3    | 4    58   1    | 6    7    25   |
 *---------------------------------------------------*


"Kraken (???)" It's neither basic, nor franken, nor mutant. And it's a single-digit chain including a finned fish where the exclusion holds when all the fins are false ... so I agree it's a Kraken swordfish.

"It only works because there's a single elimination." Do you mean the chain expression is simple because both fins are seen by the conjugate link r3c1=2=r9c1

Your expression is about as good as one can write. However, while the expression is bidirectionally correct, it is difficult to see that when the swordfish is "destroyed" one of fins must be true. So perhaps it's better to reverse the implications for people who usually only read left-to-right. Identifying the fins might help a little too. The result ...

[r7c2]-2-[r9c1]=2=[r3c1]-2-(fins [r2c3]|[r3c8])=2=(Swordfish [r467C358])-2-[r7c2]

Happy fishing and don't hesitate to put your Kraken finds in the Ultimate FISH Guide!

[daj95376]

Thanks ronk !!! I must admit, I was tired and thought trying to express the Kraken Swordfish as a chain might be fun. When something half-way meaningful resulted, I just had to share it for the irony.

By 'it only works because there's a single elimination', I meant that there is a (single) starting and ending point for the contradiction chain. I have no idea how to write it as a chain if there had been multiple eliminations. Thanks for the suggestion on reversing the chain so that people (like myself) who tend to read only from left-to-right would have a better understanding. I admit, I wasn't sure if a 'chained' interpretation for the relationship between the Swordfish and its fin cells existed.

Read a few of my posts and you'll quickly realize that I don't understand fish well enough to post any of my examples to the Ultimate Fish Guide. Most of the time, I'm struggling to know if I'm even close on interpreting a pattern. I don't want my posts to interrupt the flow of the serious work going on in that chain. However, if anyone finds one of my examples to be relevant to that chain, then please feel free to use it there.

My puzzle generator is currently configured to kick out all kinds of Templates/patterns so I can get some practice trying to spot fish. Right now, I'm working my way through a group and some of them are more than SS can explain. Unfortunately, most appear to be Kraken fish. Both of my puzzles above are from this group.

The only problem I experience, when starting with Template eliminations, is that there are often more eliminations possible for a digit than one fish can explain. I had people really confused awhile back with some of my posts because I was trying to explain all of the eliminations with one fish. Now, I try to find a simpler fish whenever they jump out at me.

[Pat]

re: Sashimi

Without the fin, the pattern degenerates, making it a true Sashimi.

Without the fin, i don't see that it "degenerates" -
all i see is a 6-cell Swordfish.

it seems i don't know the definition of Sashimi --

can there be a finless Sashimi ?

thanks
Pat

[daj95376]

[Edited: deleted original] After reading Pat's next comment, I now understand Ruud's comment. Now it makes perfect sense -- without at least one fin cell, the Sashimi Swordfish would degenerates into an X-Wing.

[Pat]

Without the fin, the pattern degenerates, making it a true Sashimi.

i see i had probably misunderstood Ruud's phrasing.

everywhere i've seen the term Sashimi, it is finned;

and i think Ruud's phrasing is to be read thus --

Without the fin, the pattern degenerates;
this qualifies the finned version as a Sashimi.

[ronk]

and i think Ruud's phrasing is to be read thus --

Without the fin, the pattern degenerates;
this qualifies the finned version as a Sashimi.

To clarify: sashimi fish ("sashimi") is finned, by definition ... but finned fish is not sashimi.

If all the fin cells of a sashimi are false then ...

One of the defining units (row, column, or box of the base set) of the fish would have a naked single.

The same statement is not true for a finned fish.

[Pat]

sashimi fish is finned, by definition ... but finned fish is not sashimi.

If all the fin cells of a sashimi are false then

One of the defining units (row, column, or box of the base set) of the fish would have a naked single.

The same statement is not true for a finned fish.

ronk, thanks, i really did need a definition for sashimi.

yet i'm still somewhat perplexed -- in the above example, without the fin, the 3 rows of the "base" will not have a "naked single" -- 2 of the rows will form an X-wing which creates a "hidden single" in the 3rd row -- is this included in your definition of sashimi ?

thanks
~ Pat

[ronk]

yet i'm still somewhat perplexed -- in the above example, without the fin, the 3 rows of the "base" will not have a "naked single" -- 2 of the rows will form an X-wing which creates a "hidden single" in the 3rd row -- is this included in your definition of sashimi ?

Sorry That definition was made hastily and should probably be deep-sixed. Without mentioning it, I was writing about the swordfish only and meant, if all the fin cells are false, the swordfish degenerates into an x-wing and a single.

Correct, this one could have 4 candidates in the fin. Without the fin, the pattern degenerates, making it a true Sashimi.

Code: Select all

# a Sashimi Swordfish !!!
 *-----------------------------------------------------------*
 | .     .    *3     |(#)    .    #3     |*3     .     .     |
 | .     .    *3     |#3     .    (#)    |*3     .     .     |
 | .     3     .     | .    -3     3     | 3     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .     .     | .     .     .     | .     .     3!    |
 | 3     .     .     | 3     .     .     | .     .     .     |
 | .     3     .     | 3     3     .     | .     .     .     |
 |-------------------+-------------------+-------------------|
 | .     .    *3     | .    *3     .     |(*)    .     .     |
 | 3     3     3     | .     .     3     | .     .     .     |
 | .     .     .     | .     .     .     | .     3!    .     |
 *-----------------------------------------------------------*


In this example -- with r1c6<>3 and r2c4<>3 -- the row sashimi swordfish in R127c357 degenerates into an x-wing in R12c37 ... causing r7c3<>3 and single r7c5. Were all the candidates shown, it would be a hidden single ... as you pointed out.

Generalizing, when all fin cells are false, if an N-fish degenerates into smaller fish, then the N-fish is sashimi -- smaller bite-sized pieces being merely "held together" by the fin.

[daj95376]

[Oops: ronk posted at the same time. dropping comment.]

[Pat]

In this example -- with r1c6<>3 and r2c4<>3 -- the row sashimi swordfish in R127c357 degenerates into an x-wing in R12c37 ... causing r7c3<>3 and naked single r7c5.

sorry, ronk, i thought i had trouble with sashimi, now it seems we merely disagree about the definitions of "naked single" vs "hidden single" --

[ronk]

it seems we merely disagree about the definitions of "naked single" vs "hidden single" --

Thanks, I agree it's a hidden single on a pencilmark grid of all candidates. Furthermore the "naked" vs. "hidden" distinction seems moot for a single-candidate grid -- so I'll try to remember to just write "single" in that context.