The New Sudoku Players' Forum

[tonyjer]

Hi

Have tried many fiendish puzzles over the years and have looked in vain for single and multiple guardians to eliminate candidates. Thing is I have not seen one possibility in all this time.

My expereince is that these mothers invariably crack with the odd finned swordfish and grouped x cycle than this much vaunted technique.

Even when I put the puzzle through Andy Stuart's solver it always bypasses these darn guardians.

Incidentally, I am finding more and more that AICs and XY chains are generating contradictions (which are helpful) but not eliminating candidates in the orthodox way. Is this fairly common?

In relation to guardians it might be my recognition skills but I just don't think so.

Your views would be much appreciated.

Gracias y vaya con dios

Antonio, Anna y Eduardo Felipe

[re'born]

Have tried many fiendish puzzles over the years and have looked in vain for single and multiple guardians to eliminate candidates. Thing is I have not seen one possibility in all this time.

I've seen a few, but not too many (full disclosure: I don't look for them very often)

My expereince is that these mothers invariably crack with the odd finned swordfish and grouped x cycle than this much vaunted technique.

I'm not sure who has been vaunting it lately.

In relation to guardians it might be my recognition skills but I just don't think so.

Are you spotting them, but they don't give eliminations, or are you just not spotting them at all? In the first case, I would suggest that the existing literature does not exploit the situation as completely as it should. For instance, on the sudopedia page for broken wing, the second example grid ignores the eliminations of the candidates in r2c5 and r5c2. My experience was always that people only looked for eliminations outside of the pattern.

Finally, check out this thread if you haven't already. It has some example of broken wings where it isn't always obvious what an alternative move to make the same or similar elimination would be.

[daj95376]

Yes, Guardian cells are way too much trouble!!! However ...

Code: Select all

PM sdaj_01_11a
 +-----------------------------------------------------------------------+
 |  8      17     1679   |  3      79     5      |  169    2      4      |
 |  59     3      1569   |  2      8      4      |  1569   159    7      |
 |  4      57     2      |  79     1      6      |  589    3      589    |
 |-----------------------+-----------------------+-----------------------|
 |  579    2      789    |  4      379    1      |  3589   6      589    |
 |  3      157    14579  |  79     6      8      |  1459   1459   2      |
 |  19     6      489    |  5      39     2      |  3489   7      189    |
 |-----------------------+-----------------------+-----------------------|
 |  2      9      15     |  8      4      3      |  7      15     6      |
 |  157    4      3      |  6      25     79     |  259    8      159    |
 |  6      8      57     |  1      25     79     |  2459   459    3      |
 +-----------------------------------------------------------------------+


Code: Select all

Guardians cells work here (or a UR Type 4)
+-----------------------------------+
|  .  .  .  |  .  .  5  |  .  .  .  |
|  5  .  5  |  .  .  .  |  5  5  .  |
|  .  5  .  |  .  .  .  |  5  .  5  |
|-----------+-----------+-----------|
|  5  .  .  |  .  .  .  |  5  .  5  |
|  .  5  5  |  .  .  .  |  5  5  .  |
|  .  .  .  |  5  .  .  |  .  .  .  |
|-----------+-----------+-----------|
|  .  .  5  |  .  .  .  |  .  5  .  |
|  5  .  .  |  .  5  .  | -5  .  5  |
|  .  .  5  |  .  5  .  | -5  5  .  |
+-----------------------------------+


Code: Select all

I'm not sure about here
+-----------------------------------+
|  .  .  9  |  .  9  .  |  9  .  .  |
|  9  .  9  |  .  .  .  |  9  9  .  |
|  .  .  .  |  9  .  .  |  9  .  9  |
|-----------+-----------+-----------|
|  9  .  9  |  .  9  .  |  9  .  9  |
|  .  .  9  |  9  .  .  |  9  9  .  |
|  9  .  9  |  .  9  .  |  9  .  9  |
|-----------+-----------+-----------|
|  .  9  .  |  .  .  .  |  .  .  .  |
|  .  .  .  |  .  .  9  | -9  .  9  |
|  .  .  .  |  .  .  9  | -9  9  .  |
+-----------------------------------+


[tonyjer]

Many thanks for your advice.

Truth is I just don't spot em outside the examples given.

Will go back to drawing board.

Antonio. Anna, y Eduardo Felipe