You know this is not the final coordinates of the cache!
Here is a Antiknight sudoku.
Sudoku (数独)is a logic-based,combinatorial number-placement puzzle. The objective is to fill a 9×9 grid with digits so that each column, each row, and each of the nine 3×3 subgrids that compose the grid contains all of the digits from 1 to 9. The puzzle setter provides a partially completed grid, which for a well-posed puzzle has a single solution. But this is a AntiknightSudoku not a basic Sudoku. The rules:
Fill in the space with numbers 1 ~ 9, so that each line, each column and every number within the hospital are not repeated. Each of the two forms of chess in the horse's position can not fill in the same number.