With the exception of mail from Mainland China, postal codes are not used in Hong Kong as the Hongkong Post deems it unnecessary to adopt such a system. Hongkong Post advised to leave the postcode field blank or try to fill in with "000", "0000", "000000" or "HKG" wherever required.[1] The People's Republic of China's national postal service, China Post, has allocated postal code 999077 to Hong Kong, although this is only sporadically used when sending mail from Mainland China.[2] As China Post does not serve Hong Kong, this code is generally not used in any other scenarios and remains little-known.[2]