Almost a thousand Japanese immigrant workers arrived monthly in California in the early 1900's. Tension grew over the Japanese as it was feared they would depress wages. A 'Gentlemen’s Agreement' was designed in which Japan agreed not to issue passports to emigrants to the United States and the US withdrew discrimatory laws against the Japanese. The Gentlemen's Agreement was made effective on 18 February 1908.
Japan continued to issue passports for emigration to Hawai'i, from where immigrants could move on to the US relatively easy. 180.000 Japanese migrated to Hawai'i between 1885 and 1924.
Read more? Eiichiro Azuma, 'Japan's Colonial Expansionism in Transpacific Migration' in: Connecting Seas and Connected Ocean Rims (Leiden 2011)