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

| 1 | | 7 | | | 9 | | | | C | D | | |

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

| | | | 2 | | | | | | | | | D |

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

| A | | 8 | | | 5 | | | C | 9 | | | |

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

| | | | | | | | 2 | | | | | 4 |

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

| | A | B | | | 6 | | | 1 | | | | 9 |

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

| | | | | | | | | | 3 | | | |

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

| C | | | 4 | | A | | | | | | | 1 |

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

| | | | A | | | | | | | C | D | |

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

| 3 | 5 | | | 9 | 7 | | | | | | 2 | C |

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

| B | | D | | | | 2 | | | | | | |

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

| | 6 | | | | | 3 | | | | | | |

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

| | | A | | 6 | 2 | | 5 | | | 8 | | |

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

| | | | | | | B | | | 5 | 7 | | |

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

Fill the 13x13 grid so that each row, column, left diagonal and right diagonal has values {1-9ABCD}. The definitions of "left/right diagonals" are explained (hopefully quite clearly) here. I also explain there that this is essentially a simple Sudoku variant, with each cell belonging to 4 houses (rows, cols, left diags, right diags).

This introductory puzzle is solvable with naked singles only. For P&P solvers, I recommend drawing up a grid in which the diagonals to which each cell belongs are marked in the left and right corners. For example, with a 5x5 grid, something like this:

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

|a z|b y|c x|d w|e v|

| | | | | |

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

|b v|c z|d y|e x|a w|

| | | | | |

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

|c w|d v|e z|a y|b x|

| | | | | |

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

|d x|e w|a v|b z|c y|

| | | | | |

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

|e y|a x|b w|c v|d z|

| | | | | |

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

One line puzzle for B&B solvers:

- Code: Select all
`1.7..9...CD.....2........DA.8..5..C9..........2....4.AB..6..1...9.........3...C..4.A......1...A......CD.35..97.....2CB.D...2.......6....3........A.62.5..8........B..57..`