When it comes to trade, a country has certain rules to follow. It is a mix of hard facts and assumptions/preferences.

There are hard facts that cannot be ignored, such as (1) a country cannot export to itself, and (2) a country cannot trade with its own free zone if it follows the general trade system.

However, there are also assumptions and preferences to consider. For instance, if a country only imports from itself, it’s likely that these are re-imports. In this case, the re-imports would be created. If a country follows the special trade system, then trade with itself can be explained as trade with its free zones.

For more information about trade systems, please refer to the IMTS Concepts and Definitions and IMTS Compiler Manual.