There were signs that if the Japs were coming, if they were going to give trouble, it would be on the opposite side of the perimeter from the Matanikau, not where the Goettge patrol met its fate, but on the eastern side, out beyond the Tenaru. On August 12, a platoon from the 1st Marines, out on patrol, walked into a white man who turned out to be a Catholic priest, a Marist father who, like Captain Clemens, had chosen to stay on the island despite the Japanese. His news was that a large Jap force was in the area.
Just about a week later, on August 19, a company-strength patrol from the same regiment marched through the same area, looking for the Japanese. The lieutenant who had commanded the earlier patrol went along, and when Captain Brush, in command, chose a lunch stop, the lieutenant urged him to go on another mile to a village where the lieutenant said he had seen oranges.
A march for chow, as any Marine knows, is not a march at all. They went on and surprised a Japanese patrol of thirty-four men. In fifty-five minutes of lively action, thirty-one of the enemy were killed. A look at the bodies showed that this was no ordinary Japanese patrol. Too many of the uniforms were officers'. *
Plainly, the Division action report says, the Japanese were reinforcing their Guadalcanal garrison.
--The Old Breed
*Captured documents retrieved off the dead Japanese officers included a map which described in graphic detail the marines' defenses along Alligator Creek (aka the Teneru River during the Guadalcanal campaign). From this, HQ divined an attack from the east was imminent.