The New Sudoku Players' Forum

by **wapati** » Wed Dec 20, 2006 10:44 pm

claudiarabia wrote:
This one has BUG 2 , x-wing, xy-wing, an y-cycle and a turbot fish. Do you consider cycles as forcing chains?

Claudia

I used an x-wing (or two) and a skyscraper to a dead end for patterns.

At this stage I saw many short-xy-chains, each of which solved it, nice puzzle! (Short being one cell past an xy wing.)

I have no idea whether a y-cycle is a chain.
I have usually found a finned fish to by-pass one such,
but I didn't in this case.

by **claudiarabia** » Thu Dec 21, 2006 4:11 pm

ronk"][quote="claudiarabia wrote:
Code: Select all
2 . . 4 . . . . 9 . 5 . . 8 . . 6 . . . 9 . . 3 4 . . 8 . . . . . 6 . 2 . . 1 . . 8 . . . 6 . . . . . 7 . 1 . . 3 . . 4 2 . . . 7 . . 3 . . 1 . 1 . . 8 . . . . 4

This one has BUG 2 , x-wing, xy-wing, an y-cycle and a turbot fish. ..What is a "BUG 2"? [A pencilmark grid illustrating the "BUG 2" for this puzzle would be appreciated.]

TIA, Ron

Code: Select all: *--------------------------------------------------* | 2 1 68 | 4 57 67 | 38 35 9 | | 3 5 4 | 29 8 29 | 1 6 7 | | 7 68 9 | 16 15 3 | 4 2 58 | |----------------+----------------+----------------| | 8 3 7 | 5 4 1 | 6 9 2 | | 9 2 1 | 7 6 8 | 5 4 3 | | 6 4 5 | 3 29 29 | 7 8 1 | |----------------+----------------+----------------| | 5 689* 3 | 16- 19 4 | 2 7 68 | | 4 7 28 | 29 3 56 | 89 1 56 | | 1 69- 26- | 8 27 567* | 39 35 4 | *--------------------------------------------------*

We have two three-value-cells in r7c2 and r9c7 where the 6 disturbes the bug-symmetry. Regardless, were in these two cells the 6 will appear finally (it has to appear in one of them) they eliminate the 6 in r7c4 and r9c23 because these three cells see the 6 as well as in r7c2 and r9c7(Overlapping of influence of box/line). By elimination of the 6 in r7c4 and r9c23 in this cells remains one candidate and the puzzle is solved.

Claudia

by **ArkieTech** » Thu Dec 21, 2006 4:51 pm

Code: Select all: *--------------------------------------------------* | 2 1 68 | 4 57 67 | 38 35 9 | | 3 5 4 | 29 8 29 | 1 6 7 | | 7 68 9 | 16 15 3 | 4 2 58 | |----------------+----------------+----------------| | 8 3 7 | 5 4 1 | 6 9 2 | | 9 2 1 | 7 6 8 | 5 4 3 | | 6 4 5 | 3 29 29 | 7 8 1 | |----------------+----------------+----------------| | 5 689* 3 | 16- 19 4 | 2 7 68 | | 4 7 28 | 29 3 56 | 89 1 56 | | 1 69- 26- | 8 27 567* | 39 35 4 | *--------------------------------------------------*

If there was only one three value cell it would be a BUG type 1 and the three value cell could be replaced by the disturbing number (6).

In this case there are two three value cells r7c2 and r9c7. If neither of the three value cells can not "see" each other would these cells always take on the disturbing number as they do in this case? Or am I missing something?

dan

by **claudiarabia** » Thu Dec 21, 2006 11:11 pm

ArkieTech wrote:
Code: Select all
*--------------------------------------------------* | 2 1 68 | 4 57 67 | 38 35 9 | | 3 5 4 | 29 8 29 | 1 6 7 | | 7 68 9 | 16 15 3 | 4 2 58 | |----------------+----------------+----------------| | 8 3 7 | 5 4 1 | 6 9 2 | | 9 2 1 | 7 6 8 | 5 4 3 | | 6 4 5 | 3 29 29 | 7 8 1 | |----------------+----------------+----------------| | 5 689* 3 | 16- 19 4 | 2 7 68 | | 4 7 28 | 29 3 56 | 89 1 56 | | 1 69- 26- | 8 27 567* | 39 35 4 | *--------------------------------------------------*

In this case there are two three value cells r7c2 and r9c7. If neither of the three value cells can not "see" each other would these cells always take on the disturbing number as they do in this case? Or am I missing something?

dan

Hi Dan,

it is not sure that both of the 3-value cells will turn in the end to the BUG-disturbing number. Sometimes it happens sometimes not. Important is, what they both eliminate as candidates together, because this is the key of solving the bug. These two cells are behaving like the wings of an xy-wing which can eliminate numbers in two boxes, given one of the two wing-cells is in the same box as the center-cell is.

This BUG is put in the group Type 2 because you can eliminate candidates outside the formation (i.e. the BUG-center-cells). Unique rectangle Type 2 for instance allows you the elimination of candidates outside the rectangle because it is clear, that this candidate has to be part of the rectangle to avoid 2 solutions. The case is the same in BUG type 2. The 6 has to be part of the BUG-Center-Cells and thus have to be eliminated outside the BUG-Cells in the two areas where the two 6es have cross-interference.

BUG Typ2's with three BUG-center-cells with the same disturbing candidate can also be found.

Claudia

by **ronk** » Fri Dec 22, 2006 2:19 am

claudiarabia wrote:We have two three-value-cells in r7c2 and r9c7 where the 6 disturbes the bug-symmetry.
(...)

Thanks for the illustration.

So "BUG 2" was shorthand for "BUG+n Type 2" ... where n=2 or n=3. Each of the polyvalued cells must be trivalued ... and the extra non-BUG candidate of each trivalue must be the same digit.

Is that correct?

by **wapati** » Fri Dec 22, 2006 3:51 am

For patterns, this is stupendous.

Jellies are rare, a finned jelly awaits!

Tons of patterns, to get there.

Hardest pattern puzzle that I have seen, that has fins.

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

by **wapati** » Sat Dec 23, 2006 12:08 am

Pretty tough pattern puzzle.

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

by **Carcul** » Sun Dec 24, 2006 12:42 pm

Wapati wrote:Pretty tough pattern puzzle.

Code: Select all: *----------------------------------------------------* | 23 5 1 | 679 23 67 | 79 4 8 | | 8 4 7 | 139 5 13 | 39 2 6 | | 9 23 6 | 4 8 237 | 5 37 1 | |-----------------+------------------+---------------| | 6 89 3 | 5 1 4 | 2 89 7 | | 5 7 4 | 2 9 8 | 6 1 3 | | 12 1289 289 | 36 7 36 | 4 89 5 | |-----------------+------------------+---------------| | 4 38 5 | 378 6 9 | 1 37 2 | | 123 6 28 | 1378 4 1237 | 37 5 9 | | 7 1239 29 | 13 23 5 | 8 6 4 | *----------------------------------------------------*

[r9c2]-1-[r8c1]-{ATILA: r1c15|r3c6|r8c16}-7-[r8c7]-3-[r8c1]-2-[r8c3]-
-8-[r6c3]-9-[r9c3]=9=[r9c2], => r9c2<>1 solving the puzzle.

Merry Christmas, Carcul

by **claudiarabia** » Sun Dec 24, 2006 4:13 pm

ronk"][quote="claudiarabia wrote:Thanks for the illustration.
So "BUG 2" was shorthand for "BUG+n Type 2" ... where n=2 or n=3. Each of the polyvalued cells must be trivalued ... and the extra non-BUG candidate of each trivalue must be the same digit.

Is that correct?

Yes, totally correct.

Claudia

by **wapati** » Tue Dec 26, 2006 4:01 am

Nothing terribly hard but several stages, in the pattern sense.

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

Merry Christmas!

by **ArkieTech** » Tue Dec 26, 2006 7:11 pm

Had fun with this one.

Code: Select all: *-----------* |.8.|.9.|.5.| |93.|..4|28.| |6..|5..|...| |---+---+---| |26.|4..|..5| |..3|...|9..| |7..|..5|.64| |---+---+---| |...|..3|..2| |.21|9..|.48| |.7.|.5.|.9.| *-----------*

dan

by **Carcul** » Wed Dec 27, 2006 2:06 pm

ArkieTech wrote:Had fun with this one.

Code: Select all: *----------------------------------------------------* | 1 8 27 | 2367 9 267 | 4 5 367 | | 9 3 5 | 167 167 4 | 2 8 67 | | 6 4 27 | 5 23 8 | 137 137 9 | |----------------+-----------------+-----------------| | 2 6 8 | 4 17 9 | 137 137 5 | | 4 5 3 | 167 8 167 | 9 2 17 | | 7 1 9 | 23 23 5 | 8 6 4 | |----------------+-----------------+-----------------| | 58 9 6 | 18 4 3 | 157 17 2 | | 35 2 1 | 9 67 67 | 35 4 8 | | 38 7 4 | 128 5 12 | 6 9 13 | *----------------------------------------------------*

[r3c5]-2-[r1c6]=2|1=[r5c6]-1-[r4c5]-7-[r4c78]=7=[r3c78]-7-[r3c3]-2-
-[r3c5], => r3c5<>2.

Carcul

by **ArkieTech** » Wed Dec 27, 2006 3:40 pm

Carcul said:

Code: Select all
*----------------------------------------------------* | 1 8 27 | 2367 9 267 | 4 5 367 | | 9 3 5 | 167 167 4 | 2 8 67 | | 6 4 27 | 5 23 8 | 137 137 9 | |----------------+-----------------+-----------------| | 2 6 8 | 4 17 9 | 137 137 5 | | 4 5 3 | 167 8 167 | 9 2 17 | | 7 1 9 | 23 23 5 | 8 6 4 | |----------------+-----------------+-----------------| | 58 9 6 | 18 4 3 | 157 17 2 | | 35 2 1 | 9 67 67 | 35 4 8 | | 38 7 4 | 128 5 12 | 6 9 13 | *----------------------------------------------------*

[r3c5]-2-[r1c6]=2|1=[r5c6]-1-[r4c5]-7-[r4c78]=7=[r3c78]-7-[r3c3]-2-
-[r3c5], => r3c5<>2.

Is that an XY-chain with fins

dan

by **claudiarabia** » Thu Dec 28, 2006 3:56 pm

udosuk wrote:
ronk wrote:Your persistence and patience with Carcul's riddles amazes me.

Not every riddle, just this one and perhaps another from a very long time ago... For the others I didn't bother much...

I didn't view it as a riddle anyway... Just trying to figure out a move along his descriptions... At the end I failed miserably...

Hi,

I followed Carcul's steps and found out the following:

Code: Select all: *-----------* |...|.5.|9.7| |.92|.73|.18| |.7.|49.|.2.| |---+---+---| |.5.|.6.|79.| |9.7|5..|..1| |.2.|9..|485| |---+---+---| |2..|..5|.79| |.19|..6|8..| |.3.|.89|...| *-----------* *--------------------------------------------------------------------* | 13468 468 13468 | 1268 5 128 | 9 346 7 | | 456 9 2 | 6 7 3 | 56 1 8 | | 13568 7 13568 | 4 9 18 | 356 2 36 | |----------------------+----------------------+----------------------| | 1348 5 1348 | 1238 6 1248 | 7 9 23 | | 9 468 7 | 5 234 248 | 236 36 1 | | 136 2 136 | 9 13 17 | 4 8 5 | |----------------------+----------------------+----------------------| | 2 468 468 | 13 134 5 | 136 7 9 | | 457 1 9 | 237 234 6 | 8 345 234 | | 4567 3 456 | 127 8 9 | 1256 456 246 | *--------------------------------------------------------------------*

-3-[r23c7](-6-[r3c9|r5c7])-6-[r7c7]=6|4=[r7c5]-4-[r8c5]-{TITILA}.
So, r3c7=3 and the puzzle is solved.

Carcul wants to explain:

If r3c7 doesn’t contain 3 à a naked pair of 56 is coming into existence in r23c7. that means that in r3c9, r5c7 and r7c7 there is no 6 because they all see the naked pair.

While so in r7c7 there are only 13 remaining, they form another naked pair with r7c4 upon the values 13, leaving 4 in r7c5. From this carcul concludes that r8c5 can’t contain 4.

Now I try to describe the ominous TITILA:
After placing the 3 in r3c9, you place then the 2 in r4c9. When you complete the column 9 and the box down right it follows for the row 7 that you have 1 in r7c7 and 3 in r7c4. So this Naked Pair is solved for this moment. For the row 5 the placing of 2 in r4c9 means that 3 is in r5c7 and 6 in r5c8. When the 4 is in r7c5 (as carcul found out) it means for the r5 that 4 is in r5c6 while a 2 is in r5c5.

And now comes the TITILA: I suppose it means a contradiction; that a cell will stay empty, because it’s values are to be seen in the surrounding cells. The empty cell in our case is r8c5, while we put it’s candidates already in the cells to be seen in the surrounding of r8c5, i.e. the 3 in r7c4, 4 in r7c5, 2 in r5c5.

That means we have to keep the 3 in r3c7, as Carcul already pointed out.

I hope I understood Carcul correctly.

With best wishes

Claudia

by **udosuk** » Thu Dec 28, 2006 4:25 pm

Claudia, your puzzle isn't the one of Carcul's riddle... It's another one from wapati, which Carcul just solved casually with his usual "complex forcing chains"...

Carcul's riddle is from this puzzle, where you've already spotted a nice xy-wing... Carcul just wanted us to solve it using uniqueness patterns only...

The New Sudoku Players' Forum

CHAINS, not required. Good puzzles.

Re: a cycle

BUG2

BUG2-centercells all will have disturbing candidate finally?

Re: BUG2

Re: BUG2

Carcul's TITILA

Re: Carcul's TITILA