The New Sudoku Players' Forum

[Yogi]

......3.16...4....2.........1.3.8...5......6....7..2......2.64..3.........8......

[Leren]

Code: Select all

*----------------------------------------*
| 8 4   59 | 2569 b57 26 | 3  a2579  1   |
| 6 579 3  | 259   4  1  | 8   2579  5-7 |
| 2 579 1  | 8     3  79 | 4   579   6   |
|----------+-------------+---------------|
| 9 1   2  | 3     6  8  | 57  57    4   |
| 5 8   7  | 24    9  24 | 1   6     3   |
| 3 6   4  | 7     1  5  | 2   8     9   |
|----------+-------------+---------------|
| 7 59  59 | 1     2  3  | 6   4     8   |
| 4 3   6  | 59    8  79 | 57  1     2   |
| 1 2   8  | 46   c57 46 | 9   3    d57  |
*----------------------------------------*

Skyscraper : (7) r1c8 = r1c5 - r9c5 = (7) r9c9 => - 7 r2c9; stte

Leren

[eleven]

For manual solvers. Not hard to come her (hidden pair 46 in r9 does not help):

Code: Select all

 +-------+-------+-------+
 | 8 4 . | . X ° | 3 * 1 |
 | 6 . 3 | * 4 1 | 8 . X |
 |#2 . 1 | 8 3 . |#4 .#6 |
 +-------+-------+-------+
 | 9 1 2 | 3 6 8 | . . 4 |
 | 5 8 7 | . 9 ° | 1 6 3 |
 | 3 6 4 | 7 1 5 | 2 8 9 |
 +-------+-------+-------+
 | 7 . . | 1 2 3 | 6 4 8 |
 |#4 3#6 | . 8 . | . 1#2 |
 | 1 2 8 | . X ° | 9 3 X |
 +-------+-------+-------+

Hidden triple 246 in r159c6.
57 in cells X (r19c5, r29c9). This is an obvious Remote Pair (here a double skyscraper), so 57 can't be in the starred cells r1c8,r2c4.
That leaves only r1c5 for 7 in r1.

[Leren]

eleven wrote : 57 in cells X (r19c5, r29c9). This is an obvious Remote Pair (here a double skyscraper), so 57 can't be in the starred cells r1c8,r2c4.

That was the same solution as Hodoku. I would have thought the Skyscraper was simpler.

Leren

[eleven]

Yes, it is in some way, because the 5 is not needed.
But a skyscraper is not as easy to spot as these obvious "rest pairs" 57.

[Yogi]

After the Locked Pair 79r38c6 it was the Double Skyscraper that interested me as a P&P solver.
I wrote it as {57c59} => r1c8<>7 => 9r3c6 stte
Different language, but I think that's the same appoach as some of you, although I saw solving r3c6 as the key to the whole puzzle.
Yogi