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Ninja Sudoku
http://www.rcbroughton.co.uk/sudoku/forum/viewtopic.php?f=4&t=847
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Author:  simon_blow_snow [ Sat Nov 20, 2010 12:33 pm ]
Post subject:  Ninja Sudoku

Don't mistake this Gattai variant with Kazagurama, which has a similar shape. This one is much more tightly packed. In fact, it can fit on a 19x19 square board, the minimum anyone can do with 4 non-overlapping 9x9 grids and 1 overlapped 9x9 central grid.

Note the central grid overlaps each of the 4 outside grids on 20 cells (roughly 1/4 of the total area), so there is only 1 cell on the central grid which is not overlapped, the absolute minimum with 4 non-overlapping outside grids.

(As for the name, both Ninja and Samurai are historic roles/occupations in Japan, and both these 2 variants consist of 5 subgrids, with 1 central grid overlapping 4 outside grids.)

Ninja Sudoku

Image

Note all 5 subgrids are Ninjutsudoku grids. You can find information about the Ninjutsudoku variant in here.

Author:  simon_blow_snow [ Sat Nov 20, 2010 12:39 pm ]
Post subject:  Re: Ninja Sudoku

Here is a puzzle with 8 initial givens (out of 325 cells!):

Ninja Sudoku #1
Image

I will not say this puzzle is "human solvable". But I will say it is "ninja solvable", so if you think you have the sudoku solving skills better than normal players as a ninja would have over normal humans, please feel free to attack it. ;-)

I will release the solution, and perhaps the solving method, later.

Author:  enxio27 [ Sat Nov 20, 2010 9:24 pm ]
Post subject:  Re: Ninja Sudoku

Probably beyond my skills, but I would love to try an easier one if someone can find or make one.

Author:  simon_blow_snow [ Mon Nov 22, 2010 1:10 pm ]
Post subject:  Re: Ninja Sudoku

Just for enxio27, here is a highly human solvable (HHS) puzzle.

I just dropped many extra constraints, leaving only the bloom petals and nothing else (so the puzzle is made up of 5 Bloomdoku grids). Instead there are lots of initial givens, so the puzzle is probably shamelessly non-minimal.

To distinguish this one with the original, more restrained "Ninja" variant, I decide to name this one "Kunoichi Sudoku". Google the word if you want to know the meaning.

Kunoichi Sudoku #1

An error was made when creating this puzzle, causing it to have 4 solutions.
To obtain a unique solution, add the following condition:
G1 (top-left) R6C4 = G5 (bottom-right) R4C6 = 5



Image

text representation:
x=central grid, #=grid boundary
Code:
#2.6.1.3.5#########
#.1.3.5.7.4.8.9.2.6
#3.......8.9.2.6.1.
#.2.....3.2.......7
#6.......1.4.....2.
#.3..xxxxxxxxx....9
#7...xxxxxxxxx...5.
#.8.9xxxxxxxxx....2
#9.3.xxxxxxxxx.2.8.
5.1.2xxxxxxxxx8.9.5
.2.8.xxxxxxxxx.7.1#
8....xxxxxxxxx1.2.#
.5...xxxxxxxxx...3#
1....xxxxxxxxx..7.#
.8.....6.9.......4#
3.......8.7.....8.#
.9.4.8.1.2.......7#
4.8.1.2.6.3.5.7.9.#
#########5.7.9.4.8#

line codes for the 4 outside 9x9 subgrids:
Code:
Top-Left
2.6.1.3.5.1.3.5.7.3.......8.2.....3.6.......1.3.......7.........8.9.....9.3......

Top-Right
4.8.9.2.6.9.2.6.1.2.......7.4.....2.........9.......5.........2.....2.8.....8.9.5

Bottom-Left
5.1.2.....2.8.....8.........5.......1.........8.....6.3.......8.9.4.8.1.4.8.1.2.6

Bottom-Right
......7.1.....1.2.........3.......7.9.......4.7.....8.2.......7.3.5.7.9.5.7.9.4.8

text solution:
Code:
#276418395#########
#418395276418597236
#395276418597236418
#521649837236418597
#649837521649853721
#837521649853721649
#762184953721649853
#184953762184975362
#953762184975362184
5316298475362184975
629847531629843751#
847531629843751629#
752164983751629843#
164983752164985372#
983752164985372164#
315296478372164985#
296478315296438517#
478315296438517296#
#########517296438#

Author:  HATMAN [ Wed Nov 24, 2010 9:21 am ]
Post subject:  Re: Ninja Sudoku

Excellent packing Simon

Author:  enxio27 [ Wed Nov 24, 2010 3:13 pm ]
Post subject:  Re: Ninja Sudoku

simon_blow_snow wrote:
Just for enxio27, here is a highly human solvable (HHS) puzzle.

Thank you so much! I'm taking it with me on my Thanksgiving holiday trip.

Quote:
To distinguish this one with the original, more restrained "Ninja" variant, I decide to name this one "Kunoichi Sudoku". Google the word if you want to know the meaning.

:) Goes well with my avatar, don't you think?

Author:  HATMAN [ Sat Nov 27, 2010 8:03 pm ]
Post subject:  Re: Ninja Sudoku

Indeed it does

Author:  enxio27 [ Tue Nov 30, 2010 4:50 am ]
Post subject:  Re: Ninja Sudoku

I've gotten the Kunoichi as far as working out all of the pencil marks. It was a little easier than I expected, but I tried a different method this time that will hopefully eliminate exasperating mistakes.

Here are the pencil marks for the five grids, if someone is willing to double-check them for me:

Grid #1:
Code:
.-------------------------------.-------------------------------.-------------------------------.
| 2         479       6         | 478       1         4789      | 3         49        5         |
| 48        1         489       | 3         24689     5         | 2469      7         2469      |
| 3         4579      4579      | 2467      24679     24679     | 12469     12469     8         |
:-------------------------------+-------------------------------+-------------------------------:
| 1458      2         145789    | 145678    456789    146789    | 456789    3         4679      |
| 6         4579      45789     | 24578     2345789   24789     | 245789    24589     1         |
| 1458      3         145789    | 1245678   2456789   1246789   | 2456789   245689    24679     |
:-------------------------------+-------------------------------+-------------------------------:
| 7         456       1245      | 124568    234568    123468    | 1245689   1245689   23469     |
| 145       8         1245      | 9         234567    123467    | 124567    12456     23467     |
| 9         456       3         | 1245678   245678    124678    | 1245678   124568    2467      |
'-------------------------------.-------------------------------.-------------------------------'


Grid #2:
Code:
.-------------------------------.-------------------------------.-------------------------------.
| 4         1357      8         | 1357      9         1357      | 2         3         6         |
| 357       9         357       | 2         3457      6         | 3458      1         348       |
| 2         1356      1356      | 13458     1345      13458     | 3458      349       7         |
:-------------------------------+-------------------------------+-------------------------------:
| 1356789   4         135679    | 1356789   13567     135789    | 13678     2         138       |
| 135678    1235678   123567    | 1345678   1234567   134578    | 134678    3467      9         |
| 136789    123678    123679    | 1346789   13467     134789    | 134678    5         1348      |
:-------------------------------+-------------------------------+-------------------------------:
| 1356789   135678    1345679   | 1345679   134567    134579    | 13467     3467      2         |
| 135679    13567     1345679   | 1345679   134567    2         | 13467     8         134       |
| 1367      12367     123467    | 13467     8         1347      | 9         3467      5         |
'-------------------------------.-------------------------------.-------------------------------'


Grid #3:
Code:
.-------------------------------.-------------------------------.-------------------------------.
| 2456789   1246789   2456789   | 245689    24679     135678    | 1235678   123567    1345678   |
| 234568    123468    1245689   | 1245689   23469     136789    | 123678    123679    1346789   |
| 234567    123467    124567    | 12456     234567    1356789   | 135678    1345679   1345679   |
:-------------------------------+-------------------------------+-------------------------------:
| 245678    124678    1245678   | 124568    2467      135679    | 13567     1345679   1345679   |
| 34679     346789    34789     | 3479      123456789 1367      | 12367     123467    13467     |
| 1345679   1345679   34579     | 134579    3468      245689    | 2345689   234689    234568    |
:-------------------------------+-------------------------------+-------------------------------:
| 1345679   1345679   234579    | 1234579   34678     45689     | 345689    346789    345678    |
| 1234679   134789    234789    | 123479    14678     1245689   | 1245689   246789    245678    |
| 2345679   345789    2345789   | 234579    13468     124568    | 1234568   1234689   1234568   |
'-------------------------------.-------------------------------.-------------------------------'


Grid #4:
Code:
.-------------------------------.-------------------------------.-------------------------------.
| 5         3467      1         | 3679      2         34679     | 346789    34789     3479      |
| 679       2         34679     | 8         345679    1345679   | 1345679   34579     134579    |
| 8         3467      34679     | 135679    345679    1345679   | 1345679   234579    1234579   |
:-------------------------------+-------------------------------+-------------------------------:
| 2679      5         234679    | 123679    34679     1234679   | 134789    234789    123479    |
| 1         3467      234679    | 235679    3456789   2345679   | 345789    2345789   234579    |
| 279       8         23479     | 123579    34579     1234579   | 134579    6         1234579   |
:-------------------------------+-------------------------------+-------------------------------:
| 3         167       2567      | 25679     5679      25679     | 4579      4579      8         |
| 267       9         2567      | 4         3567      8         | 357       1         357       |
| 4         7         8         | 3579      1         3579      | 2         3579      6         |
'-------------------------------.-------------------------------.-------------------------------'


Grid #5:
Code:
.-------------------------------.-------------------------------.-------------------------------.
| 3468      245689    2345689   | 234689    234568    2345689   | 7         456       1         |
| 34678     45689     345689    | 346789    345678    1         | 5689      2         569       |
| 14678     1245689   1245689   | 246789    245678    245689    | 5689      456       3         |
:-------------------------------+-------------------------------+-------------------------------:
| 13468     124568    1234568   | 1234689   1234568   2345689   | 123569    7         2569      |
| 9         12568     123568    | 12368     1235678   23568     | 12356     1356      4         |
| 1346      7         123456    | 123469    123456    234569    | 123569    8         2569      |
:-------------------------------+-------------------------------+-------------------------------:
| 2         14689     14689     | 13468     13468     3468      | 1356      1356      7         |
| 1468      3         1468      | 5         12468     7         | 126       9         26        |
| 5         16        7         | 1236      9         236       | 4         136       8         |
'-------------------------------.-------------------------------.-------------------------------'


Now, onward to solving!

Author:  simon_blow_snow [ Tue Nov 30, 2010 1:15 pm ]
Post subject:  Re: Ninja Sudoku

Good work enxio27. The pencilmarks look alright to me.

I was half expecting you to actually solve this "on paper". ;-)

Author:  enxio27 [ Tue Nov 30, 2010 2:52 pm ]
Post subject:  Re: Ninja Sudoku

simon_blow_snow wrote:
Good work enxio27. The pencilmarks look alright to me.

I was half expecting you to actually solve this "on paper". ;-)

I do solve it "on paper", but I think it's more than I can manage without pencil marks. I use SudokuSolver or JSudoku to help with the pencil marks, because otherwise I end up making too many mistakes on the pencil marks before I ever start solving. That takes all the fun out of sudoku for me.

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