Which battle marked the first major U.S. amphibious assault on the Mariana Islands and enabled B-29 bombers to reach Japan?

• A. Battle of Iwo Jima
• B. Battle of Tarawa
• C. Battle of Saipan
• D. Battle of Okinawa

Answer: (C)

Gaining air bases that could reach Japan with heavy bombers is the key idea. The first major amphibious assault on the Mariana Islands—Saipan—established those bases, letting B-29 Superfortresses operate from closer distances and carry out sustained strategic bombing of the Japanese home islands. From Saipan’s airfields, bombers could reach targets across Honshu and northern Japan, something that was impractical from bases farther away or from China. The other battles fit different theaters or timings: Tarawa was an earlier Pacific assault in the Gilberts and did not provide Mariana airfields; Iwo Jima, while crucial for escort and proximity to Japan, is not in the Marianas; Okinawa occurred later and was not the first Mariana invasion. So Saipan is the battle that fits both the amphibious assault and the enabling of the air campaign against Japan.