Half Sudoku (or "Sujiken") is a logic puzzle on a triangular grid of 45 cells. Your task is to fill all empty cells with numbers from 1 to 9, following these rules:
1. In each row, numbers 1-9 must not repeat.
2. In each column, numbers 1-9 must not repeat.
3. On each diagonal, numbers 1-9 must not repeat.
4. In each region marked by bold lines, numbers 1-9 must not repeat.
Some cells are already filled with numbers - these are clues that cannot be changed. Use logic to determine which numbers should be in each cell.
Pro? Record a master class and get V.I.P.