Hud wrote:I'm just curious, but do you use pcncilmarks?

Good question, Regis.

kickindaspeaker: Here is your puzzle using pencilmarks

Here is your original puzzle with pencilmarks

- Code: Select all
`+--------------+---------------+-----------------+`

| 4 1 5 | 7 3 89 | 269 689 269 |

| 7 3 9 | 48 6 2 | 1 48 5 |

| 2 8 6 | 49 1 5 | 3479 3479 79 |

+--------------+---------------+-----------------+

| 6 249 12 | 3489 47 189 | 5 379 279 |

| 3 59 8 | 2 57 6 | 79 1 4 |

| 19 2459 7 | 349 45 19 | 2369 369 8 |

+--------------+---------------+-----------------+

| 5 67 4 | 1 9 3 | 8 2 67 |

| 8 69 3 | 5 2 7 | 469 469 1 |

| 19 279 12 | 6 8 4 | 79 5 3 |

+--------------+---------------+-----------------+

Locked candidate 4 in box 2

Translation: In box 2, all 4's are in column 4; hence the 4 of column 4 must be one of those cells. Therefore all other 4's can be erased from your pencilmarks. Erase 4 from r4c4 and r6c4.

Hidden pair 24 in row 6

Translation: In row 6 there are two cells that contain candidates 2 and 4. No other cell has them. Therefore one of those two cells must be a 2 and the other a 4. Thus r6c2 cannot be 5 or 9, erase those two.

Naked pair 19 in row 6

Translation: There are two cells in row 6 that contain the pencilmarks 1 and 9. There are no other pencilmarks in those two cells. Therefore, 1 and 9 can be removed from all other cells in row 6. It turns out there are only some 9's to erase. Erase them.

Ah! r6c4 has only one candidate! Write 3 in that cell and erase all candidate 3's from any other cells in the box, row and column.

Here are your pencilmarks now.

- Code: Select all
`+-------------+-------------+-----------------+`

| 4 1 5 | 7 3 89 | 269 689 269 |

| 7 3 9 | 48 6 2 | 1 48 5 |

| 2 8 6 | 49 1 5 | 3479 3479 79 |

+-------------+-------------+-----------------+

| 6 249 12 | 89 47 189 | 5 379 279 |

| 3 59 8 | 2 57 6 | 79 1 4 |

| 19 45 7 | 3 45 19 | 26 6 8 |

+-------------+-------------+-----------------+

| 5 67 4 | 1 9 3 | 8 2 67 |

| 8 69 3 | 5 2 7 | 469 469 1 |

| 19 279 12 | 6 8 4 | 79 5 3 |

+-------------+-------------+-----------------+

(Just to show what it looks like)

Mac