Japanese Attack on Pearl Harbor in 1941

INTRODUCTION

• Surprise military strike on December 7, 1941• World War II• Preventive action • Neutralize the U.S. Pacific Fleet

INTELLIGENCE ARCHITECTURE/SYSTEM

• MAGIC– Army and Navy– Able to decode Japanese communications

• Radio traffic– Navy intelligence unit at Pearl Harbor– Able to detect and analyze location of

Japanese ships– Derive force composition and location of

Japanese Fleet through NTTI

INTELLIGENCE ARCHITECTURE/SYSTEM

• American embassy in Japan– Ambassadors’ report provide insight of

Japanese intentions and attitudes– Reflected Japanese people attitude towards

war and hostility towards the US

• Other sources– Allies provide intelligence on Japan and Far

East