The Hitachi Maru (常陸丸) was a 6,172 GRT combined passenger-cargo ship built by Mitsubishi Shipbuilding in Nagasaki, for NYK Lines in 1898.

In 1896, following the First Sino-Japanese War, NYK Lines announced an ambitious expansion plan for shipping routes to Europe, which would require up to twelve new vessels.

Although the company enlisted the support of foreign advisors and used foreign blueprints as a guide, the work took longer than expected, and Mitsubishi eventually was forced to pay compensation to NYK for the cancellation of one of the vessels, and for the delay in delivery of the vessel later named Hitachi Maru.

[1] Hitachi Maru was placed into service with NYK on its European routes for almost six years.

While transporting 1,238 people, including 727 men of the 1st Reserve Regiment of the Imperial Guard of Japan and 359 men from the IJA 10th Division and 18 Krupp 11-inch (280 mm) siege howitzers, she was shelled and sunk by the Imperial Russian Navy armored cruiser Gromoboi in the southern Korean Strait between the Japanese mainland and Tsushima in the "Hitachi Maru Incident".