HAIKOU, Dec. 18 -- Goods entering and leaving the "first line" and "second line" of the customs system of Hainan Free Trade Port (FTP) can undergo special customs clearance starting Thursday.

Such goods can move through eight "first-line" and 10 "second-line" customs ports across the tropical island.

The "first line" refers to Hainan's connection with overseas markets. Meanwhile, the "second line" denotes the customs boundary between the island and China's mainland.

Officials describe the two-tiered special customs system as "freer access at the first line," referring to freer trade between Hainan and areas outside China's customs border, and "regulated access at the second line," which means maintaining standard customs controls for China's mainland.