A Japanese family in the morning. One person — child, partner, sibling — picks up their bag and heads for the door. They pause at the genkan, slip on their shoes, and call back into the house: “itte kimasu.” Someone, possibly visible in the kitchen, possibly just a voice from another room, replies: “itterasshai.”
The exchange takes about three seconds. It happens daily, often multiple times. It’s said even when both speakers are slightly half-asleep, even when the going person is just running out for milk, even when the staying person is on a different floor and the words have to be slightly raised. The pair of phrases is one of the smallest, most consistent Japanese household rituals — and the structure of what’s being exchanged is more interesting than it looks.
What the words literally are
行ってきます (itte kimasu) is built from two verbs: iku (to go) and kuru (to come). The compound means, literally, “I will go and come [back].” The grammar is more specific than English “goodbye”: the speaker is committing, in the structure of the sentence itself, to return. Going-without-returning would not be itte kimasu; it would be sayonara or another permanent-departure phrase.
いってらっしゃい (itterasshai) is the response: itte (the te-form of “go”) + irasshai (the polite imperative-friendly form of “come” / “be”). The compound translates roughly as “go, and come [back]” — the staying person is acknowledging the going-and-returning as something they expect and welcome.
The two phrases are each other’s structural complements. The going person says “I’ll go and come back.” The staying person says “Yes, go, and do come back.” Both phrases encode the round-trip; both depend on each other.
The promise built into the grammar
This is what makes the exchange culturally distinctive. English “goodbye” is, in its etymology, “God be with you” — a blessing for the journey, no return commitment built in. “See you later” implies a return but more loosely. Japanese has plenty of words for going-without-returning (sayonara, itte mairimasu in the most formal register, others). The everyday domestic farewell is specifically the one with the return-commitment built into the verb structure.
That structural commitment matters. The household member leaving for school or work is not just saying goodbye; they are stating, in the form of the sentence itself, that they intend to return. The household member responding is acknowledging the intention. The exchange is a small recurring contract: I will come back / yes, do come back. Said hundreds of times in a relationship, it accumulates.
The uchi/soto crossing
The phrases are tied to the threshold of the home. Saying itte kimasu is performed at or near the door — most often at the genkan, the lowered entryway that separates the inside-zone of the house from the outside world. The exchange marks the crossing from uchi (inside, the in-group, the home) to soto (outside, the world).
This is consistent with the broader Japanese cultural pattern of treating uchi/soto as a real and visible boundary. The home is not a passive container; it is a category space, and entering or leaving it is something that gets ritualized. The greeting at departure is the small spoken edge of this larger structural concern. Without the words, the crossing is incomplete; with them, the boundary is acknowledged and the going person carries the household’s awareness with them as they cross into soto.
Where it’s said, and where it isn’t
The phrases are domestic. They live in households between family members, partners, or close cohabitants. They do not normally extend to:
Strangers. You don’t say itte kimasu to a barista as you leave a coffee shop.
Generic workplaces. Modern offices have largely shifted to otsukaresama desu (“you must be tired”) as the all-purpose departure greeting. Itte kimasu is sometimes used when leaving for a specific external task (“I’m going to the client meeting now”), but the response from coworkers is usually a softer version or simply “yes, please.”
Casual social contexts. Friends parting after dinner say jaa, mata (“see you again”) or other general farewells, not itte kimasu.
The phrases are reserved for the specific case of leaving (and returning to) one’s own home or shared living space. This narrowness is part of what makes them carry emotional weight. They mark a particular kind of relationship — cohabitation, family — and not a generic farewell.
The empty-house version
One small detail that surprises foreign observers: many Japanese people will say itte kimasu even when leaving an empty house — to a cat, to a family altar, to the room itself, to no one in particular. The going person is performing the side of the exchange that’s theirs to perform. The completion of the exchange — the matching itterasshai — is sometimes left implicit, with the speaker imagining the response or acknowledging the home as the listener.
This is consistent with broader Japanese folk-religious treatment of the home as having a presence — a household altar (kamidana), ancestral spirits, or just the home itself as a kind of attentive entity. Saying itte kimasu to the empty house treats the home as listener. The practice doesn’t require religious belief; it’s culturally available even to non-religious speakers.
The variations
Several common variations:
Itte kuru / itte kuru ne — casual short form. Used between close family or partners.
Itte mairimasu — formal version. Mairimasu is the humble form of “to come/go.” Used in formal contexts, by service workers leaving for an errand, or in writing.
Itterasshai standalone — the response, said as a complete utterance.
Itterasshaimase — formal extended response, used in shops and ryokan when seeing a guest off.
Ki o tsukete — “be careful” — often added to itterasshai in colder weather or when the going person is leaving on a long trip.
The pair extends naturally to the return: tadaima (I’m back) / okaerinasai (welcome back). The four phrases form a complete daily round-trip protocol — leaving, going out, returning, being received.
Using them yourself
If you are sharing a household with a Japanese partner, family, or roommate, learning these phrases is one of the highest-leverage small acts of fluency you can perform. Three rules cover most cases:
Always say itte kimasu when leaving the house, even briefly. The going person initiates. Always respond with itterasshai when someone else leaves the house. The staying person is expected to acknowledge. Carry the round trip through to the return: when you come back, say tadaima; when someone else returns, say okaerinasai. The four-phrase sequence is the full protocol; doing only half of it feels incomplete.
For a non-native partner of a Japanese person, performing this exchange consistently is a small but persistent way of signaling commitment to the household. It costs three seconds. It’s noticed every time it’s done, and every time it’s omitted.
The principle underneath
The itte kimasu / itterasshai exchange is, in its way, a small spell against the unannounced disappearance. The verb structure makes the going person commit to returning; the response makes the staying person register and welcome that commitment. The household, as a unit, is asserting that members do not just leave — they leave and come back, and both halves of the trip are spoken into existence.
This is a small ritual, but it does cumulative work. A household where these phrases are exchanged hundreds of times per year is a household with hundreds of small repeated affirmations of return. The relationships that result have, built into them, a reliable verbal architecture for one of the most ordinary anxieties of cohabitation: will the person who just left come back? The Japanese answer, performed daily, is yes — and the exchange itself is the saying-yes. The going person says it of themselves. The staying person says it back. The day proceeds, with the round trip already verbally complete, to be lived out in the next few hours.