79 years ago this month, the US District Court for China was abolished by Congress, after being in existence since 1906. Established by virtue of treaties between the US and China and by various acts of Congress, the court had civil and criminal jurisdiction over US citizens living in China and, later, in the Philippines, Guam and other US "possessions." Appeals went to the Ninth Circuit US Court of Appeals in San Francisco.
In US: must be an attorney licensed and in good standing in any state, territory or DC.
Outside US: must be a lawyer or equivalent (eg counselor, barrister, advocate, solicitor), duly educated and licensed/accredited and in good standing.
As a general rule, experienced and currently practicing lawyers, and those in the legal academy, are more likely to be admitted.