が・の (Subject)Particle Swapping

In some cases, the particle の can be used in place of が to mark a subject. This happens only in relative clauses, where the subject marked by の is not the main subject of the sentence.

There are two main reasons why someone may choose to use の instead of が.

First, if there is already another が, marking the main subject of the sentence, then it normally sounds more natural to not repeat が twice in the same sentence.

Second, が can put emphasis on the thing that it marks, delineating it specifically as new or noteworthy. Using の instead of が sounds less strong, so something else in the sentence can be emphasized.

Caution

が is not swapped for の if the clause contains an object marked by を. In such cases, の will be interpreted as the possessive particle, thus changing the meaning entirely.