The New Sudoku Players' Forum

by **lovethepirk** » Thu Feb 23, 2006 9:01 pm

This suduko is from http://www.sudokusolver.co.uk/grids_veryhard.html
It is the #3 sudoku, Difficulty score of 916

I missed a Hiddden Pair of '6' and '9' in the location R7C4 & R7C6...BUT I am wondering
if my find on the swordfish is correct or not.

I filter for 7's and they were all green.
Then I made the pairs orange
Then I think I can eliminate the purple.

Correct?

Thanks,

LTP

by **tso** » Thu Feb 23, 2006 10:28 pm

Please use text grids whenever possible. Those of us that are colorblind have no idea which cells you are refering to as being green, orange or purple. (I don't know why Simple Sudoku and some others Sudoku aps insist on using pastel colors that are nearly indistinguishable to 150 to 300 million people worldwide.) Most readers prefer to be able to copy the text into whatever app they might use. Since you are already using SS, just copy and paste.

Code: Select all: *-----------* |1..|...|.8.| |.9.|7.2|..5| |...|...|...| |---+---+---| |.5.|.6.|..2| |8..|.9.|.1.| |.3.|.4.|..7| |---+---+---| |...|...|...| |.7.|3.5|..4| |6..|...|.9.| *-----------*

Code: Select all: *--------------------------------------------------------------------------------------* | 1 246 234567 | 469 35 469 | 23467 8 369 | | 34 9 3468 | 7 138 2 | 1346 346 5 | | 3457 2468 2345678 | 14689 358 14689 | 23467 23467 1369 | |----------------------------+----------------------------+----------------------------| | 47 5 19 | 18 6 37 | 89 34 2 | | 8 246 2467 | 25 9 37 | 3456 1 36 | | 29 3 1269 | 25 4 18 | 89 56 7 | |----------------------------+----------------------------+----------------------------| | 345 1248 23458 | 14689 278 14689 | 2357 2357 138 | | 29 7 289 | 3 128 5 | 126 26 4 | | 6 1248 23458 | 148 278 148 | 2357 9 138 | *--------------------------------------------------------------------------------------*

There is no swordfish in sevens from this position.

Code: Select all: *---------------------------------------------* | . . 7 | . . . | 7 . . | | . . . | 7 . . | . . . | | 7 . 7 | . . . | 7 7 . | |--------------+---------------+--------------| | 7 . . | . . 7 | . . . | | . . 7 | . . 7 | . . . | | . . . | . . . | . . 7 | |--------------+---------------+--------------| | . . . | . 7 . | 7 7 . | | . 7 . | . . . | . . . | | . . . | . 7 . | 7 . . | *---------------------------------------------*

A Swordfish will be 6 to 9 cells that sit in exactly THREE rows and THREE columns.

I don't know what you mean by "Then I made the pairs orange". There are no pairs in a Swordfish.

I'm guessing that by "purple", you mean r3c3, r3c7 and r7c7. No, you cannot exclude these. In fact, r3c3 is actually a 7 in the solution.

by **ronk** » Thu Feb 23, 2006 10:40 pm

tso wrote:Please use text grids whenever possible. Those of us that are colorblind have no idea which cells you are refering to as being green, orange or purple. [i](I don't know why Simple Sudoku and some others Sudoku aps insist on using pastel colors that are nearly indistinguishable to 150 to 300 million people worldwide.)

Simple Sudoku allows the user to customize the colors. Perhaps you could advise us which colors would be much better.

TIA, Ron

by **Hud** » Thu Feb 23, 2006 11:08 pm

I'm not much of a swordfisher, but it's my understanding that if the only rows containing 2 or 3, 7s were rows 1,4,5, the swordfish would be legit. The 2 or 3, 7s in rows 7 and 9 make it illegitimate. Hope I got it right.

by **TKiel** » Fri Feb 24, 2006 2:31 am

Hud,

The selected cells in rows 1, 4, 5 align in four columns, so it can't be a swordfish.

Tracy

by **lovethepirk** » Fri Feb 24, 2006 3:11 pm

tso,

I will use grids from on now, I appologize. I am a newbie

Thanks for the feedback everyone else.

i still am VERY confused on Swordfish, but I am going to tutorial it and study it on my own today and I will post back here with any specific questions.

Regards,

LTP

by **Hud** » Fri Feb 24, 2006 9:48 pm

The selected cells in rows 1, 4, 5 align in four columns, so it can't be a swordfish.

Thanks Tracy, I missed that one. At first glance, I thought they were in 3 columns but not so.

by **tso** » Sat Feb 25, 2006 3:47 am

ronk wrote:Perhaps you could advise us which colors would be much better.

A good choice is to start with the three primary colors -- blue, yellow and red. I didn't put much thought to the other colors other than making them distinguishable from the primary colors and each other.

Good choices are strong, pure colors. Light and dark shades help as well. A light and a dark red, a light and a dark blue, a deep and a pale yellow. Reds or browns may be indistinguishable from greens of the same intensity.

These are the settings I currently use in Simple Sudoku. Remember, there are different types of color weakness, so don't blindly follow me. (yuk)

General colors:

Code: Select all: RED, GREEN, BLUE Dark 176, 196, 215 Pale 241, 242, 245 Filtered 255, 255, 128 Selected 255, 255, 128

Marker colors:

Code: Select all: "Blue" 0, 0, 255 "Green" 255, 0, 0 "Pink" 255, 255, 0 "Amber" 128, 64, 64

Primary blue is a little dark, making the candidates hard to see. Better might be 64, 64, 255.

by **ronk** » Sat Feb 25, 2006 12:54 pm

tso wrote:
ronk wrote:Perhaps you could advise us which colors would be much better.
These are the settings I currently use in Simple Sudoku. Remember, there are different types of color weakness, so don't blindly follow me. (yuk)

Your response is much more detailed than I was expecting. Thanks.

However, as you pointed out, the candidates *are* very difficult to read on your Blue marker color. I have the same problem with the "Amber". BTW general colors Filtered and Selected are the same. Is that a typo?

Ron

by **tso** » Sat Feb 25, 2006 4:39 pm

ronk wrote:...general colors Filtered and Selected are the same. Is that a typo?

No. It just doesn't matter to me. Those two items are never in conflict. When filtering, selected cells are only highlighted by a border. Black (0-0-0) for 'selected' actually works quite will if you prefer. The candidates are quite visible.

The New Sudoku Players' Forum

Did I catch a 500 pound swordfish?

Did I catch a 500 pound swordfish?