A more thorough explanation:

Countertrade is a type of international trade where the purchases made by an importing country are linked to purchases made by the exporting country. It is like bartering, but with modern clothes. This type of trade developed quickly in the 1970s and 1980s as a way of doing business with the USSR and Eastern European countries. However, it is not as popular now as it used to be.

One example of countertrade is when a country buys oil from another country and, in exchange, the exporting country agrees to buy goods or services from the importing country. For instance, China may buy oil from Russia and, in exchange, Russia may agree to buy Chinese-made cars.

Another example is when a country buys weapons from another country and, in exchange, the exporting country agrees to buy agricultural products from the importing country. For example, Saudi Arabia may buy weapons from the United States and, in exchange, the United States may agree to buy Saudi Arabian oil.

These examples illustrate how countertrade works. The importing country and the exporting country agree to trade goods or services instead of using money. This type of trade can be beneficial for both countries because it allows them to exchange goods or services that they need without using money.