It may seem like a simple question, but greetings are among the very first expressions you need to learn when starting a foreign language.

Japanese differs greatly from most European languages, both in its linguistic origins and vocabulary. As a result, when you are just beginning to learn Japanese, it is often difficult to analyze a phrase and guess its meaning. The quickest approach is simply to learn these expressions as complete phrases.

For example:

ただいま — “I’m home.”
いってらっしゃい — “Please go and come back.”
いってきます — “I’ll go and come back.”

In particular, いってらっしゃい and いってきます sound somewhat similar, so beginners often have trouble remembering which one is said by the person leaving and which one is said by the person staying behind.

Incidentally, いってきます literally means 「行って、来ます」 (go and come). It is not simply the Japanese equivalent of “Goodbye.” It contains the idea of going somewhere and then coming back here again.

So rather than treating it as a direct equivalent of English expressions such as See you or Bye, it is helpful to understand it as:

いってきます = “I’ll go and come back.”

Thinking of it this way gives you a better sense of what makes this expression distinctly Japanese.