Rōmaji, or ローマ字, is the romanization of the Japanese written language. Although some would argue that it is only a crutch and should be avoided, rōmaji does have its place in your repertoire – namely being the primary method of Japanese input for word processors and computers. In fact, Japanese children learn rōmaji in elementary school. That said, rōmaji is only a representation of written Japanese, and therefore should not be used as a primary means when learning the language. This can cause the formation of bad habits or misunderstandings.
There are several different systems of rōmaji. Arguably, the two most-often used systems are the Hepburn and Kunrei (訓令式) systems. The Kunrei system of rōmaji is the system taught to Japanese children in elementary school. There are a few variations of the Hepburn system. This site and our lesson notes use Revised Hepburn, which is the most common form of rōmaji used today, and is also used by the Library of Congress.