[160]  Communication Intelligence Summary, 20-21 November 1941
 
Mandates and Fourth Fleet.-The R. N. O. Palao and Palao radio stations  have remained active with the Fourth Fleet and 5 Yokosuka for days. This  is taken to indicate a coming concentration of forces in Palao which  would include the Fourth Fleet and some of the Second Fleet who has also  been active with the R. N. O. Since the activity of the Second Fleet  Commander has been so great it may be that he will assign some non- Second Fleet units to that area but just which ones is not yet known.  From information from radio sources there is no indication of any  concentration now at Palao beyond the Third Base Force which is based  there. There has been no traffic for other fleet units routed there and  the Maru traffic to Palao is far less than the normal flow to that area.  With the arrival of Siti 4 (yesterday reported as either a carrier unit  or submarine unit and now identified as a submarine squadron of the  Submarine Fleet) the concentration of naval forces in the Marshalls is  far greater than that existing at Palao.

 

(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)