CSS Stonewall was powerful armored seagoing ram built for the Confederacy late in the war, arriving in American waters too late to take action.
Stonewall was built by L. Arman at Bordeaux, France in 1863-64 for the Confederate States Government; however, the French authorities refused to permit her delivery, following strong protests by American Ministers Dayton and Bigelow. The vessel was eventually sold to Denmark via a Swedish intermediary, for use in the Schleswig-Holstein War. Because she failed to reach Copenhagen before the sudden termination of the war, the Danes refused acceptance, and title to the ram - now known as Sphinx - was returned to her builder who then sold her to the Confederates.
In December 1864 Captain T. J. Page, CSN, took command and renamed the vessel for Lieutenant General Thomas J. "Stonewall" Jackson, and in January sailed from Copenhagen for Quiberon Bay, France to receive supplies. In this period she was called Staerkodder and Olinde to allay suspicion of her actual ownership and mission. Stonewall was assigned the considerable tasks of dispersing the Federal blockading fleet off Wilmington, North Carolina, intercepting Northern commerce between California and Northern ports, attacking New England coastal cities, and destroying the Yankee fishing fleet on the Newfoundland Banks.
Unable to replenish fully in French waters, Stonewall sailed for Madeira, but ran into a severe storm and had to put in to Ferrol, Spain, for coal and repairs. While she was there the Union warships USS Niagara and USS Sacramento arrived at Coruna, only 9 miles distant. On 24 March Stonewall steamed out of Ferrol and prepared for battle; however when the Federals, believing her gun power to be too great, declined to close she bore away for Lisbon to coal before crossing the Atlantic.
She reached Nassau, New Providence, on 6 May and went from there to Havana where Page learned of the war's end. Stonewall was turned over to the Captain General of Cuba in return for money needed to pay off her crew. In July 1865 the Cuban authorities voluntarily delivered her to the United States Government, which then had her laid up at the Washington Navy Yard for the next two years.
Her next and final sale was to Japan in August 1867. She was delivered to the Japanese Shogun's government in April 1868, then reverted to American ownership and in 1869 was turned over to the forces backing the emperor. Under the name Kôtetsu, she took part in the the civil war then raging in Japan and played an important role in the naval battle of Hakodate in June 1869. In 1871, after the victory of the Imperial cause, she was renamed Azuma. The ship remained a part of Japan's combat fleet until January 1888, when she was reduced to harbor service as an accomodation hulk.