The private pilot was departing from a remote airstrip in a tailwheel equipped airplane. He reported that on the day of the accident he had already completed three round trips from the accident airstrip, ferrying passengers and supplies. He stated that during the accident takeoff run, about one-quarter down the runway, the airplane's main wheels sank into about 10 inches of soft mud. The airplane then nosed over, and sustained substantial damage to the wings, and rudder.