Definition: Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
Input: Normally a pawn moves by advancing a single square, but the first time each pawn is moved from its initial position, it has the option to advance two squares.

A pawn moves forward a single square normally. But the first time a pawn is moved it can advance two squares.