When Beato arrived in Japan in the summer of 1863, the emperor and his court were again ordering the expulsion of foreigners despite recent treaties. The radical daimyo, or lord, of the Choshu clan emphatically reinforced such orders by attacking American and European ships moving through the Straits of Shimonseki.

In retaliation, a naval expedition of American, English, French, and Dutch ships attacked Shimonoseki in August–September 1864. Beato and his friend Charles Wirgman accompanied them, sailing on a British ship from Yokohama. Beato was in his familiar element, taking photographs of the British military at a battle site.