Japanese submarines using Jaluit as base for operations according to the U.S. Joint Intelligence Committee. Daily summary dated 29 January 1942

An item referred to the J.I.C. commenting that 10 Japanese submarines seemed to be operating out of Jaluit, Marshall Islands of which four in the vicinity of Hawaii.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 50 dated 29 January 1942