Despite being chastised by Toyotomi Hideyoshi in his 1587 Kyūshū campaign, and forced back to Satsuma, they remained one of the most powerful clans in the archipelago.

After a three-month war which met stiff resistance, Satsuma captured the Ryukyuan capital of Shuri and King Shō Nei.

For the remainder of the Edo period, Satsuma influenced their politics and dominated their trading policies to take advantage of Ryukyu's tributary status with China.

As strict maritime prohibitions were imposed upon much of Japan beginning in the 1630s, Satsuma's ability to enjoy a trade in Chinese goods, and information, via Ryukyu, provided it a distinct and important, if not entirely unique, role in the overall economy and politics of the Tokugawa state.

The Shimazu continually made efforts to emphasize their unique position as the only feudal domain to claim an entire foreign kingdom as its vassal, and engineered repeated increases to their own official Court rank, in the name of maintaining their power and prestige in the eyes of Ryukyu.

This derived not only from their connection to Ryukyu, but also from the size and productive wealth of Satsuma province itself, and from their extreme distance from Edo, and thus from the shōgun's armies.

The ban on smuggling, perhaps unsurprisingly, was not so strictly enforced, as the domain gained significantly from trade performed along its shores, some ways away from Nagasaki, where the shogunate monopolized commerce.

To increase his influence in the shogunate, Nariakira engineered a marriage between Shōgun Tokugawa Iesada and his adopted daughter, Atsu-hime (later Tenshō-in).

In 1854, the first year of Iesada's reign, Commodore Perry landed in Japan and forced an end to the isolation policy of the shogunate.

However, this put Satsuma at odds with the more radical Sonnō jōi, or "revere the Emperor and repel the barbarians" faction, with Chōshū as the major supporter.

In 1862, in the Namamugi Incident an Englishman was killed by retainers of Satsuma, leading to the bombardment of Kagoshima by the Royal Navy the following year.

The shogunate entrusted Satsuma and Aizu with the protection of the Imperial court, against attempts of the Sonnō jōi faction to take over, as in the Kinmon Incident of 1864.

Saigō, however, avoided a military conflict and allowed Chōshū to resolve the issue with the Seppuku of the three perpetrators behind the attack on the Imperial palace.