Futoshiki is a mathematical puzzle where you must enter numbers into the grid so that:
1. No number is used more than once in the same row or column, while at the same time,
2. All the GREATER THAN (>) and LESS THAN (<) statements linking squares on the grid are true.
Each grid square is counted as a separate single-digit number.
Only the numbers in the squares directly adjacent to a GREATER THAN or LESS THAN symbol are used when evaluating whether the numbers logically satisfy the symbol.
Example: If these numbers are entered onto a line on the grid:
  <  
This would be logically correct as only the  and the  are taken into account to satisfy the LESS THAN statement.
How to play
When pen numbers are entered in the grid, the immediately affected pencil numbers are updated:
1. The number entered in pen will be removed from any squares on the same row or column where it has been entered in pencil.
2. Pencil numbers in the four squares surrounding the pen number will only be updated if they're linked to the central square by a GREATER THAN or LESS THAN symbol.
Please note that you may still need to update pencil numbers manually in other squares on the grid.