The New Sudoku Players' Forum

[EnderGT]

I'm more interested in how EnderGT reached the elimination [r4c8]<>9 in the first place. Another good reason to provide the original puzzle.

He probably used the UR of {89} @ r45c28 to eliminate 9 from r4c28.

bingo

[EnderGT]

Another example of the old claim that you should apply other URs before a UR Type 4.

I'll have to keep that guideline in mind, might make some puzzles easier.

[udosuk]

I'm more interested in how EnderGT reached the elimination [r4c8]<>9 in the first place. Another good reason to provide the original puzzle.

He probably used the UR of {89} @ r45c28 to eliminate 9 from r4c28.

bingo

Thank you.

And am I right to guess that you eliminated the 4 from r5c5 and r9c4 using the w-wing of [6 @ b2 locked @ r2c45; r5c4 & r9c5 from {46}]?

[EnderGT]

I'm more interested in how EnderGT reached the elimination [r4c8]<>9 in the first place. Another good reason to provide the original puzzle.

He probably used the UR of {89} @ r45c28 to eliminate 9 from r4c28.

bingo

Thank you.

And am I right to guess that you eliminated the 4 from r5c5 and r9c4 using the w-wing of [6 @ b2 locked @ r2c45; r5c4 & r9c5 from {46}]?

Actually, no.. I used the simpler XY-wing R2C5,R1C6,R8C6

[udosuk]

Actually, no.. I used the simpler XY-wing R2C5,R1C6,R8C6

Of course... And there was also an alternative XY-wing @ r1c6,r2c4,r5c6.

If you had been that good using w-wing then you should have easily solved the puzzle: 2 @ c2 locked @ r49c2, r4c1 & r9c9 from {29}.

[Carcul]

Code: Select all

 *---------------------------------------------------*
 | 4     1     6  | 7     8     29 | 5     39    239 |
 | 29    3     5  | 69    26    4  | 8     1     7   |
 | 8     7     29 | 1     3     5  | 29    4     6   |
 |----------------+----------------+-----------------|
 | 29    289   4  | 5     7     1  | 6     389   39  |
 | 1     89    3  | 46    246   26 | 7     89    5   |
 | 6     5     7  | 8     9     3  | 4     2     1   |
 |----------------+----------------+-----------------|
 | 5     249   29 | 349   1     7  | 239   6     8   |
 | 3     469   8  | 2     5     69 | 1     7     49  |
 | 7     2469  1  | 3469  46    8  | 239   5     249 |
 *---------------------------------------------------*


[r1c6]-9-[r2c4]=9=[r2c1]=2=[r4c1]-2-[r4c2]=2|3=[r4c8]-3-[r1c8]-9-
[r1c6]

and so r1c6<>9 which solves the puzzle.

[daj95376]

[r4c2]=2|3=[r4c8]

Carcul: An impressive (because I can follow it) use of a UR in the middle of a chain.

ronk, et. al.: What notation would you use for this UR?

[ronk]

[r4c2]=2|3=[r4c8]

ronk, et. al.: What notation would you use for this UR?

If presenting the NL without comment, I would only add clarification for the UR, e.g. ...

UR3(89)r45c28:(r4c2 =2|3= r4c8)

[DonM]

I suppose the AIC/Eureka notation could be something like:

(9)r2c4 = r2c1 - (9=2)r4c1 - UR3(89)r45c28:[(2)r4c2=(3)r4c8] - (3=9)r1c8 => r1c6<>9