From Nanshin: Japanese settlers in Papua and New Guinea, 1890–1949, by Hiromitsu Iwamoto (Journal of Pacific History, 1999), pp. 15-16:
Until the late 19th century the Japanese government had no policies for the South Seas. The government was preoccupied with domestic affairs, while Germany, the United States, Australia, France, Spain, Netherlands, and Britain were involved in the acquisition and exchange of tropical islands. The Japanese government’s primary concern was to centralise governance in order to build a strong empire which could not be colonised. External affairs were secondary concerns in which the government was mainly preoccupied with the removal of unequal treaties imposed by Western nations and the promotion of national prestige. Although Japan’s expansionism was shown in the 1870s in Saigō Takamori‘s claim to invade Korea, Ōkubo Toshimichi‘s decision to send a military expedition to Taiwan and the government’s declaration that the Ryūkyū Islands and Sakhalin were parts of Japan, the expansion was limited to the adjacent region. The government’s involvement in South Seas affairs was marginal and largely confined to matters of national prestige and the rights of citizens abroad.
Japan’s first involvement in the South Seas was an embarrassing episode involving emigrants to Guam. In 1868 about 40 Japanese emigrated as contract labourers to work on a plantation where a Spanish employer treated them harshly. The Japanese were treated no differently from locals and the employer did not pay their promised wages in full. Their complaint to a Spanish administrator was ignored. In 1871, after some had died due to harsh work conditions, three managed to return to Japan to report their plight. The government was astonished and the matter was discussed, but it is unknown whether it took any action to save these migrants or protested to the Spanish administration. In 1868, 153 contract labourers in Hawaii suffered a similar fate. These incidents embarrassed the Japanese government which was acutely sensitive about its national dignity but probably the government, which was just managing to survive by pacifying rebels, chose not to protest in order to avoid conflicts that it could not handle confidently. The government could only ban emigration by enforcing tight regulations to avoid further national disgrace.
However, the issue of sovereignty over the Ogasawara (also known as Bonin) Islands provided an opportunity to stimulate Japanese interest in the South Seas. Although the Tokugawa government hardly resisted when Commodore Perry demanded the opening of Japan and proclaimed US possession of the Ogasawara Islands in 1853, some vocal Meiji officials in 1875 ’emphasised the urgency of return of the islands that could connect Japanese interests to the South Seas’. The report of the Foreign Ministry to the Prime Minister explained that ‘the islands were a strategic point in the Pacific sea route, which was extremely important in Japan’s advancement in the South Sea’. Then negotiations began and the US compromised. The issue signalled the beginning of the government’s awareness of its interests in the South Seas. It was also significant in that the government promoted national dignity by recovering territory.
As the incidents in Guam and Hawaii showed, the government was aware of its weak internal position and tried not to provoke other Western nations in the South Seas until the 1880s.