Every year on the seventh day of the seventh month, Japan celebrates 七夕 (Tanabata) — the festival of the stars. It comes from an old Chinese legend: two celestial lovers, 織姫 (Orihime) the weaver and 彦星 (Hikoboshi) the cowherd, are separated by the Milky Way for the entire year, permitted to meet only on this one night when a bridge of birds spans the river of stars. People write wishes on strips of colored paper and hang them from bamboo branches. The festival has been observed in Japan since the eighth century, when Empress Kōken formalized the custom at court in 755 AD.

On the evening of July 7, 1853, the people of Edo were hanging their wishes. Some time during that night or the following morning, smoke appeared on the southern horizon of 江戸湾 (Edo-wan) — Edo Bay — and it did not move the way smoke should move. It did not drift with the wind. It moved against it.

On July 8, four American warships under Commodore Matthew Perry dropped anchor at Uraga, at the bay's southern entrance roughly thirty miles from Edo Castle. The fleet consisted of two steam frigates — the Susquehanna and the Mississippi — and two sailing sloops, the Plymouth and the Saratoga. The steam ships were the ones that frightened people most. Japanese observers had seen sailing vessels before; the Dutch traders at Nagasaki had brought those. But machines that burned coal and pushed themselves through water with spinning wheels, independent of wind and tide — these were something outside the categories Japanese naval thinking possessed.

The name arrived almost immediately. People called them 黒船 (kurofune) — black ships — because the steam engines burned coal and the hulls were tarred black. The word would outlast the ships themselves by generations. Today, in Japanese business journalism and political commentary, kurofune still appears whenever someone wants to describe a sudden, disruptive arrival of outside force that Japan is powerless to ignore.

Inside the shogunate, the response was close to paralysis. The 老中 (rōjū), the senior council that managed the government, faced a threat their institutional frameworks had never imagined. Japan's 鎖国 (sakoku) policy — the two centuries of near-total isolation maintained since the 1630s — had been premised on the idea that Japan could control its borders absolutely. Perry's ships had just demonstrated that it could not. The 73 cannon aboard those four vessels could reduce any coastal fortification in Edo Bay within range, and everyone in the government knew it.

Making matters worse: the shogun himself was dying. Tokugawa Ieyoshi had been gravely ill for weeks and would be dead by July 27 — nineteen days after Perry's arrival. The government was effectively leaderless during the most consequential foreign contact Japan had experienced in 250 years. Chief Councillor 阿部正弘 (Abe Masahiro), left to decide alone, broke with all precedent: he sent copies of Perry's demands to the daimyo and eventually to the Imperial court in Kyoto, seeking counsel the shogunate had never previously felt the need to ask for. The admission was enormous. The institution that had run Japan since 1603 was announcing, by that gesture, that it did not know what to do.

On the beaches of Edo Bay, 武士 (bushi) patrolled in full armor — swords, bows, some muskets — their silhouettes visible from the American ships. Perry looked at them through his glass and reportedly was not concerned. The gap between the two sides was not a question of courage. It was a question of centuries.

Perry delivered President Fillmore's letter on July 14 and departed, promising to return with a larger fleet for an answer. He returned in February 1854 with eight ships. On March 31, 1854, the 日米和親条約 (Nichibei Washin Jōyaku) — the Convention of Kanagawa — was signed, opening Japanese ports for the first time in 220 years. Japan's age of isolation was over. And on Tanabata's eve, in 1853, the stars that crossed the sky that night were not the ones anyone in Edo had been wishing for.