Sumo Sudoku

Sumo Sudoku is a combination of thirteen Sudoku grids with common corner blocks. Each of these thirteen puzzles cannot be solved separately; there is only one common solution.

Rules: Thirteen regular 9×9 Sudoku grids have common corner blocks. None of these grids can be solved separately, but all of them together have a unique solution. In each cell of the 9×9 grid, enter a number from the range 1–9. Each number must appear exactly once in each row, column, and block.