This book covers the design and construction of the two well-known
Sōryū and Hiryū carriers, and the lesser-known ships of the Unryū
class, and relies on original Japanese source material, including
numerous photos, drawings, and specifications. How and why the Japanese
designed and constructed the WWII-era, medium-sized Sōryū, Hiryū,
and Unryū-class aircraft carriers, and how they were operated, is
covered in detail. The Imperial Japanese Navy planned the construction
of 45 aircraft carriers from 1918 to 1943 and commissioned 25 of them
between 1922 and 1944. These types were large, medium, and small
aircraft carriers, with some converted from other warship classes, and
escort aircraft carriers remodeled from passenger ships. The medium type
presented here formed the majority, with a total of 18 planned: five
were completed, three remained in various completion stages at the end
of the Pacific War, and ten were eventually canceled.