Logic Masters Deutschland e.V.

Solve in SudokuPad

Normal Sudoku rules apply.

The fortress in the central square is larger than all four orthogonally-connected cells.

Tour of Duty:

• Draw a one-cell-wide loop through the grid which moves orthogonally and visits every cell in the grid EXCEPT the fortress.
• No cell may be visited more than once.
• The path may not pass through thick brown walls at all, and if it passes through an arrow (which it doesn't have to) it may only do so in the direction the arrow points. The arrow always points to the smaller of the two cells it connects.
• If the path turns left (anticlockwise), the digit in that cell is odd. If it turns right (clockwise), the digit in that cell is even.

Watchtowers:

• Watchtowers ♜ count the number of cells on all straight segments of path they occupy combined (so a watchtower on a corner of the path counts itself once and every other cell on both straight segments it's on once).
• All watchtowers are given; that is, any cell not on a watchtower does not have the counting property defined above.