Black ships were the western vessels which came to Edo bay in Japan and it was looked in admiration.
Step-by-step explanation:
The large battle ships engaged to insist the commencement of the trade had the exterior painted black. Those were imperial ships came from America with its funnels smoking out black smoke. Japan was considered to be ‘locked state’ as the trade relations of western countries were restricted to Dejima Islands.
But US four war ships arrived at Edo bay and endangered to attack Japan if it did not give any consent to begin trade with the West. For a couple of centuries Japan was in self-inflicted inaccessibility and after arrival of the American ships, it paved way for the trade dialogues to commence with the westerners.