In a written statement, the pilot reported that he was attempting to land the tail wheel equipped airplane on an upsloping runway. The airplane touched down normally on the asphalt runway surface. During the landing roll the airplane began to ground loop. The pilot added power in an effort to recover and the airplane continued off the runway surface. The airplane encountered a ditch and incurred damage to the left fuselage structure. The pilot reported no preimpact mechanical malfunctions or failures with the airframe or engine. He added that the wind conditions were light and variable. In the section titled RECOMMENDATION (How could this accident have been prevented) of the pilot's written report (NTSB Pilot/Operator Report, Form 6120.1), the pilot stated that he should have first practiced landings at the departure airport, as it had been awhile since he had flown. He noted in the same section that most of his flight time was conducted with landings on grass strips, where the airplane maneuvers differently than the asphalt.