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Bank Holiday 0808 Kazaguruma Special
http://www.rcbroughton.co.uk/sudoku/forum/viewtopic.php?f=13&t=236		 Page 2 of 3
Author:  tarek [ Tue Aug 26, 2008 8:15 pm ]
Post subject:  Re: Kazaguruma #03 Challenge Hint
Jean-Christophe wrote:
enxio27 wrote:
Now, can someone tell me how to take the windoku blocks OUT of the center grid in JSudoku or SudokuSolver?
In JSudoku, alt-right-click on the cell and "Remove: g3:w..." for all 9 windows of the center grid (incl. the hidden ones).
Thanks JC for a very helpful update, I can use it now to display a visual supplement to the hint.

The solution path reaches its Zenith when there are no more Singles, intersections nor doubles available.

Look in grid 5 for a very nice naked triple (not needed)
The hidden triple that kills the puzzle can be seen in grid 3
However, the 2 x-wings available (with a similar effect & both not needed) are in grid 4
Visual state of the grid at the Hint Stage:
Image
Code:
Grid 4 of Kazaguruma #03
------------------------.------------------------.------------------------
| 2378    2368    2378   | 367     4       1      | 239     359    -2357   |
| 1       2345    9      | 357     358     358    | 3467    367     2347   |
| 357     3456    3457   | 3567    9       2      | 348     1       348    |
 ------------------------+------------------------+------------------------
| 6       1235    1235   | 8       2357    357    | 3479    3579    3457   |
| 23578   2358    23578  | 9       6       4      | 238     358     1      |
| 9       3458    3458   | 1235    12357   37     | 3678    3678    235678 |
 ------------------------+------------------------+------------------------
| 2358    7       3568   | 235     2358    9      | 1       4       368    |
| 4       9       368    | 13      1378    3678   | 5       2       368    |
| 2358    12358   12358  | 4       2358    3568   | 367     3678    9      |
'------------------------'------------------------'------------------------'
Author:  tarek [ Wed Aug 27, 2008 4:02 pm ]
Post subject:  Challenge solution
Here is the rundown of non single techniques needed to solve Kazaguruma #02. The results differ if a solver spots hidden doubles prior to Intersections giving that particular solver a shorter solution path.
Kazaguruma #02 non-single techniques required to solve:
1. Kazaguruma #02 intersections before hidden doubles:
81 x intersections
6 x Hidden doubles

2. Kazaguruma #02 hidden doubles before intersections:
19 x Hidden doubles
21 x intersections


Glyn (on the Players' Forum) has correctly discovered one of the x-wings of Kazaguruma #03... There were actually 2 that gave a similar result
Kazaguruma #03 X-wings:
X-wings in Kazaguruma #03:
Code:
------------------------.------------------------.------------------------
|*2378    2368    2378   | 367     4       1      | 239     359    -2357   |
| 1       2345    9      | 357     358     358    | 3467    367     2347   |
| 357     3456    3457   | 3567    9       2      | 348     1       348    |
 ------------------------+------------------------+------------------------
| 6       1235    1235   | 8       2357    357    | 3479    3579    3457   |
|*23578   2358    23578  | 9       6       4      | 238     358     1      |
| 9       3458    3458   | 1235    12357   37     | 3678    3678    235678 |
 ------------------------+------------------------+------------------------
|*2358    7       3568   |*235    *2358    9      | 1       4       368    |
| 4       9       368    | 13      1378    3678   | 5       2       368    |
|*2358    12358   12358  | 4      *2358    3568   | 367     3678    9      |
'------------------------'------------------------'------------------------'
2 forms an x-wing in g4c1b8/g4r7w9 ===> [g4r1c9]<>2 (which can also be written as [g3r4c3]<>2)
w9: r159c159

------------------------.------------------------.------------------------
| 2378    2368    2378   | 367     4       1      | 239     359    -2357   |
| 1       2345    9      | 357     358     358    | 3467    367    *2347   |
| 357     3456    3457   | 3567    9       2      | 348     1       348    |
 ------------------------+------------------------+------------------------
| 6       1235    1235   | 8      *2357    357    | 3479    3579    3457   |
| 23578   2358    23578  | 9       6       4      | 238     358     1      |
| 9       3458    3458   |*1235   *12357   37     | 3678    3678   *235678 |
 ------------------------+------------------------+------------------------
| 2358    7       3568   | 235     2358    9      | 1       4       368    |
| 4       9       368    | 13      1378    3678   | 5       2       368    |
| 2358    12358   12358  | 4       2358    3568   | 367     3678    9      |
'------------------------'------------------------'------------------------'
2 forms an x-wing in g4r6w7/g4c9b5 ===> [g3r4c3]<>2 (which can also be written as [g3r4c3]<>2)
w7: r234c159
Author:  enxio27 [ Mon Mar 02, 2009 7:39 pm ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
Jean-Christophe wrote:
In JSudoku, alt-right-click on the cell and "Remove: g3:w..." for all 9 windows of the center grid (incl. the hidden ones).

Revisiting this: What do you mean by the "hidden" windows? I'm counting only four windows in the center grid.
Author:  Para [ Mon Mar 02, 2009 8:36 pm ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
Hi

Basically these type of grids have hidden windows. They are implied because there's 2 windows of 9 cells in 3 rows. Because the 3 rows have 1-9 3 times and the 2 windows use 1-9 2 times, the remaining 9 cells in those 3 rows will have 1-9 1 time, basically creating a hidden window.

Image
Each colour is a house, which has to contain 1-9 once.

http://www.sudopedia.org/wiki/Windoku: if you want to read more.

Hope this helps.
Author:  enxio27 [ Mon Mar 02, 2009 8:47 pm ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
Para wrote:
Basically these type of grids have hidden windows. They are implied because there's 2 windows of 9 cells in 3 rows. Because the 3 rows have 1-9 3 times and the 2 windows use 1-9 2 times, the remaining 9 cells in those 3 rows will have 1-9 1 time, basically creating a hidden window.

Ok, I see that. Now, if I eliminate the four MARKED windows from the center grid, will that also remove the HIDDEN windows from that grid, or do I have to remove them separately?
Author:  tarek [ Tue Mar 03, 2009 11:05 am ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
Hi enxio27,

Your last question is more difficult to answer because it is related to a specific software (JSudoku) ....

Information from the main 4 windows are enough to give you the solution without resorting to the Hidden ones.

The hidden ones become handy because they can make the solution path easier for a solver.

When JC says remove them .... Then my feeling would be that the extra windows need to be removed as well. because they would have all been turned on when you select a windoku ... If you have to remove Each of the 4 main windows individually then you will need to remove the rest as well.

tarek
Author:  enxio27 [ Mon Jun 22, 2009 1:27 am ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
I've finally gotten to these puzzles in my "to do" puzzle pile. I had already opened them in JSudoku and fixed the "extra" windows as Jean-Christophe described earlier in the thread. However, when I have JSudoku try to solve the first one (so I can see whether the techniques required are within my abilities), I get an error:

"Cannot Deduce All Moves because Hidden Single because Cannot set RFC8 to 7 because Gf:G7 must include 7."

Can someone help me decipher that? I get similar errors for the other two puzzles.

While we're at it, would someone please confirm the grid numbering for me (i.e. which grid is #3, #4, and #5)?

(I wish SudokuSolver could handle these puzzles so that I could print each grid separately.)
Author:  tarek [ Mon Jun 22, 2009 8:52 pm ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
The numbering of overlapping grids is usually Left to right & top to bottom
So in the Kazaguruma it should be:
Image
With JSudoku, When I did it following JC explanation, it seemed that you have to choose the correct constraint to remove especially if a certain cell is within several contraints.

tarek
Author:  enxio27 [ Tue Jun 23, 2009 12:25 am ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
Thanks, tarek! I discovered that JSudoku gave me some incorrect pencil marks (which could very well be the result of a mistake on my part in following the instructions to remove the extraneous grids). I decided it was easier to import the puzzles into SudokuSolver, then add the windoku constraints and manually remove the extra pencil marks from the windoku nonets myself. Besides, SudokuSolver lets me print each grid separately. I'll see how I do with the puzzle now.
Author:  enxio27 [ Fri Jul 03, 2009 12:35 am ]
Post subject:  Re: Bank Holiday 0808 Kazaguruma Special
I guess the third time's a charm (it helps having the correct pencil marks). I finished #1 last night. It's a very nice puzzle, fairly easy, but not too easy. There was an elusive hidden single in grid 5 that evaded me for a while, even after I completed the other three outer grids. I'm finding that for puzzles with more grids (and thus more time-consuming), I prefer to have a somewhat easier puzzle than for single-grid 9x9 puzzles.

Now I'm working on #2.
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