1350 degrees oven. For the crumb mixture: grease 8" square baking dish. Mix together the oats, flour, brown sugar, baking soda, and butter until well blended. Press half the crumb mixture into the prepared baking dish.
For the filling: stir together the dates, water and cup of sugar in a small saucepan. Cook and stir over medium heat until bubbly and smooth. Pour the date mixture evenly over the crumb mixture. Spread the remaining half of the crumb mixture over the filling. Bake for 25 - 30 minutes, or until golden brown. Cut into squres and serve when cool.