The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

*-----------*
 |...|...|...|
 |..4|3.5|8..|
 |.2.|9.7|.1.|
 |---+---+---|
 |.78|...|65.|
 |...|...|...|
 |.51|...|43.|
 |---+---+---|
 |.1.|2.3|.9.|
 |..3|6.8|7..|
 |...|...|...|
 *-----------*

Play/Print this puzzle online

[Leren]

Code: Select all

*--------------------------------------------------------------------------------*
| 7       3       9        |c18      68      16       | 2       4       5        |
| 1       6       4        | 3       2       5        | 8       7       9        |
| 8       2       5        | 9       4       7        | 3       1       6        |
|--------------------------+--------------------------+--------------------------|
| 39      7       8        |c14      39     a24       | 6       5       1-2      |
| 36      4       2        | 157     356     16       | 9       8       17       |
| 69      5       1        |c78      689    -29       | 4       3      b27       |
|--------------------------+--------------------------+--------------------------|
| 4       1       6        | 2       7       3        | 5       9       8        |
| 5       9       3        | 6       1       8        | 7       2       4        |
| 2       8       7        | 45      59      49       | 1       6       3        |
*--------------------------------------------------------------------------------*

ALS XY Wing (2=7) r6c9 - r6c4 = 4 r4c4 (ALS r146c4) -(4=2) r4c6 => r4c9, r6c6 <2>

Leren

[ArkieTech]

Another one

Code: Select all

 *--------------------------------------------------*
 | 7    3    9    | 18   68   16   | 2    4    5    |
 | 1    6    4    | 3    2    5    | 8    7    9    |
 | 8    2    5    | 9    4    7    | 3    1    6    |
 |----------------+----------------+----------------|
 | 39   7    8    |a14   39   24   | 6    5    12   |
 | 36   4    2    |c157  356  16   | 9    8   c17   |
 | 69   5    1    | 78   689  29   | 4    3    27   |
 |----------------+----------------+----------------|
 | 4    1    6    | 2    7    3    | 5    9    8    |
 | 5    9    3    | 6    1    8    | 7    2    4    |
 | 2    8    7    |b45   59   49   | 1    6    3    |
 *--------------------------------------------------*
 als xy-wing
 (1=4)r4c4-(4=5)r9c4-(5=71)r5c49 => -1r5c6; stte


[Marty R.]

Code: Select all

+--------+------------+--------+
| 7  3 9 | 18  68  16 | 2 4 5  |
| 1  6 4 | 3   2   5  | 8 7 9  |
| 8  2 5 | 9   4   7  | 3 1 6  |
+--------+------------+--------+
| 39 7 8 | 14  39  24 | 6 5 12 |
| 36 4 2 | 157 356 16 | 9 8 17 |
| 69 5 1 | 78  689 29 | 4 3 27 |
+--------+------------+--------+
| 4  1 6 | 2   7   3  | 5 9 8  |
| 5  9 3 | 6   1   8  | 7 2 4  |
| 2  8 7 | 45  59  49 | 1 6 3  |
+--------+------------+--------+


Play this puzzle online at the Daily Sudoku site

I have a question. There is a BUG+3 in box 5 with the killers being 169 in r5c4, r5c5 and r6c5, respectively. This pseudo cell combines with r5c6 to form a triple. However, if you play it one way it solves the puzzle, or another way leads to an invalidity. Should that happen? Is there something wrong with what I did?

At any rate, I used an XY-Chain.

(7=8)r6c4-(8=1)r1c4-(1=6)r1c6-(6=1)r5c6-(1=7)r5c9=>r5c4,r6c9<>7

[ArkieTech]

I have a question. There is a BUG+3 in box 5 with the killers being 169 in r5c4, r5c5 and r6c5, respectively. This pseudo cell combines with r5c6 to form a triple. However, if you play it one way it solves the puzzle, or another way leads to an invalidity. Should that happen? Is there something wrong with what I did?

This is just a guess since the proof is still unclear to me The killers are 1 6 and 9 but 6 and 9 live in the same cell r6c5. This leaves only the 1 in r5c4 as the only killer. Selecting 6 still leaves a dp in 9 and 9 leaves a dp in 6. It can't be a triple because 16|9 is different from 169. I think

sounds like a "big thinker" problem.

[Marty R.]

sounds like a "big thinker" problem.

Unfortunately, I ain't one of those.

[daj95376]

Code: Select all

+--------+------------+--------+
| 7  3 9 | 18  68  16 | 2 4 5  |
| 1  6 4 | 3   2   5  | 8 7 9  |
| 8  2 5 | 9   4   7  | 3 1 6  |
+--------+------------+--------+
| 39 7 8 | 14  39  24 | 6 5 12 |
| 36 4 2 | 157 356 16 | 9 8 17 |
| 69 5 1 | 78  689 29 | 4 3 27 |
+--------+------------+--------+
| 4  1 6 | 2   7   3  | 5 9 8  |
| 5  9 3 | 6   1   8  | 7 2 4  |
| 2  8 7 | 45  59  49 | 1 6 3  |
+--------+------------+--------+


I have a question. There is a BUG+3 in box 5 with the killers being 169 in r5c4, r5c5 and r6c5, respectively. This pseudo cell combines with r5c6 to form a triple. However, if you play it one way it solves the puzzle, or another way leads to an invalidity. Should that happen? Is there something wrong with what I did?

Marty,

You were thissssssss close to utilizing the BUG+3 and r5c6 -- i.e., one of r5c4=1, r5c5=6, r6c5=9 must be true. Now, all you need is:

Code: Select all

(1)r5c4 - (1=6)r5c6 - (6)r6c5
(6)r5c5 -             (6)r6c5
(9)r6c5 -             (6)r6c5


From there, the puzzle reduces to a BUG+1 with r5c4=1.

[tlanglet]

I initially found the two step solution noted by Danny, but them spotted a one step solution.

ANP(17=5)r5c94-(5=4)r9c4-(4=1)r4c4 => r5c6<>1

[David P Bird]

There is a BUG+3 in box 5 with the killers being 169 in r5c4, r5c5 and r6c5, respectively. This pseudo cell combines with r5c6 to form a triple.

Code: Select all

+--------+------------+--------+
| 7  3 9 | 18  68  16 | 2 4 5  |
| 1  6 4 | 3   2   5  | 8 7 9  |
| 8  2 5 | 9   4   7  | 3 1 6  |
+--------+------------+--------+
| 39 7 8 | 14  39  24 | 6 5 12 |
| 36 4 2 | 157 356 16 | 9 8 17 |
| 69 5 1 | 78  689 29 | 4 3 27 |
+--------+------------+--------+
| 4  1 6 | 2   7   3  | 5 9 8  |
| 5  9 3 | 6   1   8  | 7 2 4  |
| 2  8 7 | 45  59  49 | 1 6 3  |
+--------+------------+--------+

The way you combined your 3 disrupting candidates with (16)r5c6 is very ingenious. It boils down to saying that at least one node out of (1&6)r5c456 and (9)r6c5 must be true. This produces the chain:

(1&6)r5c456 =[MUG]= (9)r6c5 – (9=3)r4c5 – (3)r4c1 = (3)r5c1 => r5c1 <> 6

Unfortunately this doesn't completely solve the puzzle, but who cares, it's clever!

There is a much smaller (369)r456c15 Deadly Pattern available too.

I'm not a great fan of these MUG patterns though as, unless they're blindingly obvious, I can usually find an elimination chain quicker.