Final answer:
The US annexation of Hawaii in 1898 played a significant role in increasing Japanese immigration to the West Coast of the United States, particularly as laborers in agriculture such as the sugar industry.
Step-by-step explanation:
In 1898, the US annexation of Hawaii increased Japanese immigration to the West Coast, predominantly in Californian territories. The Japanese government was actively involved in managing the emigration of its people and had established contractual agreements to provide labor abroad. Following the Chinese Exclusion Act of 1882, the Japanese began to fill the labor void, especially within the sugar plantations of Hawaii. The strategic importance of Hawaii burgeoned during the Spanish-American War, leading to its annexation by the United States which subsequently solidified the islands as a gateway for Japanese immigrants venturing further into America.
Despite the increase in Japanese immigration, this also coincided with rising nativist sentiments leading to the Gentleman's Agreement of 1907, aimed at curbing the immigration without causing diplomatic tensions. This unofficial agreement allowed the Japanese government to restrict the issuance of passports for those intending to immigrate to the U.S., even though it publicly proclaimed the freedom to migrate. The immigration patterns played a crucial role in the socio-economic fabric along the Pacific region, significantly contributing to the growth of the American agricultural industry.