Yokosuka Naval District

The location of Yokosuka at the entrance to strategic Tokyo Bay was recognized of critical importance by the Tokugawa shogunate and early Meiji government.

The new facility was intended to produce modern, western-style warships and equipment for the Tokugawa navy.

In a further administrative re-organization of the Japanese Navy in 1889, Yokosuka was designated as the “First Naval District” (第一海軍区, dai-ichi kaigunku), and its harbor was dredged, a breakwater extended and docking facilities for warships were increased.

On January 14, 1917, the armoured cruiser Tsukuba exploded and sank in Yokosuka port in an accident.

[4] Yokosuka was bombed by United States Navy and United States Army Air Forces aircraft in the final stages of the Pacific War, most notably during the attack on Yokosuka on 18 July 1945, but many of its facilities were captured intact by the Allied forces.