A Ryukyuan vessel had been shipwrecked near the southern tip of Taiwan in December 1871, and fifty-four members of its crew of sixty-six had been beheaded by the Paiwan aborigines.

The remaining twelve crewmen had been rescued by Han Chinese and had been transferred to Tainan in southern Taiwan.

The local Chinese government officials had transferred them to Fujian province in mainland China, whence the Qing government had arranged to send them back home.

The Meiji government of Japan demands that the Chinese government punish leaders of the Taiwanese aborigines responsible for the murders of the Ryukyuan crew.

The Japanese foreign minister Soejima Taneomi had gone to Beijing, and had been received in an audience by the Qing Emperor Tongzhi (in itself a diplomatic triumph); however, his request for compensation had first been rejected because China considers it an internal affair, since Taiwan is part of Fujian Province of China and the Ryūkyū Kingdom has a tributary relationship with China.

When Soejima Taneomi had claimed that four of the victims murdered were from Oda Prefecture, present-day Okayama Prefecture, Japan and asked for compensation again, Chinese officials had refused him on the grounds that most of the Taiwanese aborigines were outside effective Chinese control, and were thus sometimes exempt from judicial action.

Charles Le Gendre, the French-born American military advisor to the Japanese government, as well as Gustave Emile Boissonade, legal advisor, has urged that Japan take the matter into its own hands.

The Japanese government agrees, and sends an expedition of thirty-six hundred soldiers led by Saigō Tsugumichi in May 1874.