Joint Base Pearl Harbor-Hickam in Honolulu in Honolulu County, Hawaii — Hawaiian Island Archipelago (Pacific Ocean)
Dedicated to the Officers and Men of the 14th Naval District Combat Intelligence Unit
Commanding Officer: LCDR Joseph J. Rochefort, USN
Photographed by Clayton Pickett, July 28, 2023
1. Dedicated to the Officers and Men of the 14th Naval District Combat Intelligence Unit Marker
In the early months following the surprise attack on Pearl Harbor (December 7, 1941), a group of dedicated men in the Combat Intelligence Unit labored in this basement of the 14th Naval District Headquarters to decipher the Japanese naval code. This unit is known as "Hypo" but a more proper designation is "Fleet Radio Unit Pacific" (FRUPAC). Code name "Hypo", then the standard name for the "H" flag in the International Signal Code, was sometimes used loosely for the whole activity and thus applied here.
Under the inspirational leadership of LCDR Joseph J. Rochefort, USN. These cryptanalysts had decoded a few key words in the Japanese naval code (JN-25), and concluded that the code letters "AF" stood for Midway Atoll. When Midway sent out a bogus message that the atoll had experienced a serious casualty in the fresh water system, the Japanese signaled that "AF" was having trouble with its fresh water distillation system. Armed with this intelligence report and with deep confidence in Rochefort's team, Nimitz placed three American carriers 240 miles northeast of Midway to ambush the Japanese task force and reinforced
this page online
Erected 1999 by International Midway Memorial Foundation.
Topics. This historical marker is listed in these topic lists: Communications • War, World II. A significant historical date for this entry is June 4, 1942.
Location. 21° 20.999′ N, 157° 57.276′ W. Marker is in Honolulu, Hawaii, in Honolulu County. It is in the Joint Base Pearl Harbor-Hickam. It can be reached from Russell Avenue 0.1 miles west of Central Avenue, on the right when traveling west. Touch for map. Marker is at or near this postal address: 517 Russell Ave, Honolulu HI 96818, United States of America. Touch for directions.
Regionally, this marker is on Hawaii’s Pearl Harbor and Historic West Oahu. Globally, it is in North America, Polynesia, the Pacific Ocean, North Pacific, the Pacific Rim, the Western Hemisphere, the Western World, and the Anglosphere.
Other nearby markers. At least 8 other markers are within one mile of this marker, measured as the crow flies: U.S.S. Missouri (approx. 0.8 miles away); a different marker also named U.S.S. Missouri (approx. 0.9 miles away); Fleet Admiral Chester W. Nimitz, USN (approx. 0.9 miles away); The Golden Anchor (approx. 0.9 miles away); USS West Virginia Memorial (approx. 0.9 miles away); This Sacred Site (approx. 1.1 miles away); U.S. Naval Base Pearl Harbor (approx. 1.1 miles away); U.S.S. Arizona Memorial (approx. 1.1 miles away). Touch for a list and map of all markers in Honolulu.
Credits. This page was last revised on June 16, 2026. It was originally submitted on June 8, 2026, by Clayton Pickett of Richland, Washington. This page has been viewed 24 times since then. Photo 1. submitted on June 8, 2026, by Clayton Pickett of Richland, Washington. • Devry Becker Jones was the editor who published this page.
Editor’s want-list for this marker. A wide shot of the marker in context. • Can you help?
