USD / JPY

USD / JPY
In this example the U.S. dollar is the base currency and thus the "basis" for buying / selling.

If you think that the Japanese government to weaken the yen in order to help its export industry, will make buying USD / JPY order. With that you have bought U.S. dollars in the expectation that they will increase in comparison to the Japanese yen.

If you believe that Japanese investors are pulling money out of U.S. financial markets and converting all their U.S. dollars back to yen, and it will hurt the U.S. dollar, will be carried Sales USD / JPY order. With that you have sold U.S. dollars in the expectation that they will depreciate against the Japanese yen.