Battle of Shimonoseki Straits The Battle of Shimonoseki Straits ( Japanese : 下関海戦 , " Shimonoseki Kaisen " ) is a little - known naval engagement fought on July 16 , 1863 , by a warship of the United States Navy , the USS " Wyoming " , against the powerful feudal Japan ese daimyo , Lord Mori Takachika of the Chōshū clan based in Shimonoseki . The USS " Wyoming " under Captain David McDougal sailed into the strait and single - handedly engaged the US - built but poorly manned Japanese fleet . Engaged for almost two hours before withdrawing , McDougal sank two enemy vessels and severely damaged the other one , and inflicted some forty Japanese casualties . The " Wyoming " suffered considerable damage with 4 crew dead and 7 wounded . The battle was a prelude to the larger - scale 1863 and 1864 Shimonoseki Campaign by allied foreign powers . It took place among the troubled events of the Late Tokugawa shogunate from 1854 to 1868 , associated with the opening of Japan to the European and American powers . Background . In 1863 the Japanese Emperor Kōmei , breaking with centuries of imperial tradition and dissatisfied with Japan ' s opening to the United States and Europe , began to take an active role in matters of state and issued on March 11 and April 11 , 1863 , an " Order to expel barbarians " ( 攘夷実行の勅命 ) . The Shimonoseki based Chōshū clan , under Lord Mori , followed on the order , and began to take actions to expel all foreigners from the date fixed as a deadline , May 10 on a lunar calendar . Openly defying the shogunate , Mori ordered his forces to fire without warning on all foreign ships traversing Shimonoseki Strait . The Chōshū clan was equipped with mostly antiquated cannon firing round shot , but also some modern armament , such as five 8 - inch Dahlgren gun s which had been presented to Japan by the United States , and three steam warships of American construction ; the barque " Daniel Webster " of six guns , the brig " Kosei " of ten guns ( originally the " Lanrick " ) , and the steamer " Koshin " of four guns ( originally the " Lancefield " ) . Attacks on foreign shipping . The first attack occurred on June 25 , 1863 . The American merchant steamer " Pembroke " , under Captain Simon Cooper , was riding at anchor outside Shimonoseki Strait , when intercepted and unexpectedly fired upon by two European - built warships belonging to the Choshu clan . The crew of one enemy vessel taunted the frantic American seamen with the loud and unnerving cry , " Revere the Emperor and drive out the barbarians ! " ( " 尊皇攘夷 " , pronounced " Sonnō Jōi " ) . Under incessant cannon fire , " Pembroke " managed to get under way and escape through the adjacent Bungo Strait , with only slight damage and no casualties . Upon arrival in Shanghai , Cooper filed a report of the attack and dispatched it to the U . S . Consulate in Yokohama , Japan . The next day , June 26 , the French naval dispatch steamer " Kienchang " was also riding at anchor outside the strait when Japanese artillery , atop the bluffs surrounding Shimonoseki , opened fire on her . Damaged in several places , the French vessel escaped with one wounded sailor . On July 11 , despite warnings from the crew of the " Kienchang " , with whom they had rendezvoused earlier , the 16 - gun Dutch warship " Medusa " cruised into Shimonoseki Strait . Her skipper , Captain François de Casembroot was convinced that Lord Mori would not fire on his vessel , due to the strength of his ship and longstanding relations between the Netherlands and Japan . But Mori opened fire , pounding " Medusa " with more than thirty shells and killing or wounding nine seamen . De Casembroot returned fire and ran the rebel gauntlet at full speed , fearful of endangering the life of the Dutch Consul General , who was then aboard " Medusa " . Within a short time , the Japanese warlord had managed to fire on most of the foreign flags of nations with consulates in Japan . Battle . In the morning of July 14 , 1863 , under sanction by Minister Pruyn , in an apparent swift response to the attack on the " Pembroke " . At 4 : 45 a . m . on 14 July , Comdr . McDougal called all hands ; and " Wyoming " got under way 15 minutes later , bound for the strait . After a two - day voyage , she arrived off the island of Himeshima on the evening of 15 July and anchored off the south side of that island . At five o ' clock in the following morning , " Wyoming " weighed anchor and steamed toward the Strait of Shimonoseki . She went to general quarters at nine , loaded her pivot gun s with shell , and cleared for action . The warship entered the strait at 10 : 45 and beat to quarters . Soon , three signal guns boomed from the landward , alerting the batteries and ships of Lord Mori of " Wyoming ' s " arrival . At about 11 : 15 , after being fired upon from the shore batteries , " Wyoming " hoisted her colors and replied with her 11 - inch pivot guns . Momentarily ignoring the batteries , McDougal ordered " Wyoming " to continue steaming toward a bark , a steamer , and a brig at anchor off the town of Shimonoseki . Meanwhile , four shore batteries took the warship under fire . " Wyoming " answered the Japanese cannon " as fast as the guns could be brought to bear " , while shells from the shore guns passed through her rigging . USS " Wyoming " then passed between the brig and the bark on the starboard hand and the steamer on the port , steaming within a pistol shot ' s range . One shot from either the bark or brig struck near " Wyoming ' s " forward broadside gun , killing two men and wounding four . Elsewhere on the ship , a Marine was struck dead by a piece of shrapnel . " Wyoming " , in hostile territory , then grounded in uncharted waters shortly after she had made one run past the forts . The Japanese steamer , in the meantime , had slipped her cable and headed directly for Wyoming — possibly to attempt a boarding . The American man - of - war , however , managed to work free of the mud and then unleashed her 11 - inch Dahlgren s on the enemy ship , hulling her and damaging her severely . Two well - directed shots exploded her boilers and , as she began to sink , her crew abandoned the ship . " Wyoming " then passed the bark and the brig , firing into them steadily and methodically . Some shells were " overs " and landed in the town ashore . As Comdr . McDougal wrote in his report to Secretary of the Navy Gideon Welles on 23 July , " the punishment inflicted and in store for him will , I trust , teach him a lesson that will not soon be forgotten . " After having been under fire for a little over an hour , " Wyoming " returned to Yokohama . She had been hulled 11 times , with considerable damage to her smokestack and rigging . Her casualties had been comparatively light : four men killed and seven wounded — one of whom later died . Significantly , " Wyoming " had been the first foreign warship to take the offensive to uphold treaty rights in Japan . The two Japanese steamers sunk by the " Wyoming " were raised again by Chōshū in 1864 and attached to the harbor of Hagi . The results of the battle were not sufficient to stop the actions of the Choshu clan against foreign shipping and the shore batteries of Choshu remained intact . The shelling of foreign ships continued . Foreign powers would later combine into a powerful fleet in 1864 in order to conduct the Shimonoseki Campaign , with successful results .