[176]   Communication Intelligence Summary, 4 December 1941
 
General.-Traffic volume normal with fair receiving conditions. Takao  Radio today instituted a fleet broadcast system using the prefix UTU in  heading so that there are now two fleet broadcasts in operation. So far  only a few messages have been placed on the Takao broadcast. There were  a large number of urgent messages, today, most of these from Tokyo to  the major commanders. Among others Tokyo Intelligence originated a seven  part message to Chiefs of Staff China Fleet, Combined Fleet, Third  Fleet, South China Fleet, French Indo-China Force and Sama. In all, this  activity sent twelve messages to the major commanders.
Combined Fleet.-The outstanding item of today's traffic is the lack of  messages from the CinC. Second Fleet and CinC. Third Fleet. These  previously very talkative commanders are now very quiet. While the Fleet  calls are not yet well identified, the lack of traffic from these  commands cannot be ascribed to that. These two commands are still  prominent as addressees. It is now believed that the CinC. Second Fleet  is in the vicinity of Takao and that the apparently conflicting evidence  is due to traffic destined for the Tokyo UTU broadcast which CinC.  Second Fleet is still copying. The CinC. Combined Fleet sent one message  to an unidentified unit for information to Third Base Force Palao, CinC.  Second Fleet and CinC. Third Fleet.
Fourth Fleet.-The CinC. Fourth Fleet sent a message to Chief of Staff  Combined Air Force, information to Eleventh Air Corps, Chitose Air, Air  Squadron Twenty-four, Third Base Force at Palao and Fourth Base Force at  Truk. No further check could be made today on the presence of Fourth  Fleet units in the Marshalls. Jaluit appeared many times in today's  traffic being associated with Commander Submarine Force, Tokyo Radio and  MUSI 88 (which is believed to be an oil tanker).
South China.-Bako continues as an active originator addressing many  messages to Sama and Saigon. Except for traffic between South China  Commanders, all units in that area quiet.
 
(FROM: U.S. CONGRESS JOINT COMMITTEE ON PEARL HARBOR ATTACK HEARINGS; PT.  35, THE CLAUSEN INVESTIGATION, PP. 62-81. EXHIBIT "A" DAILY COMMUNICATION INTELLIGENCE SUMMARIES)