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N4Lesson notes · Oct 3, 2026

Let's Go in Japanese: 行いこう, 行いくぞ and the 行いきましょう you actually use with adults

"Let's go" in Japanese is 行いこう with friends and 行いきましょう with anyone you should be polite to — and 行いくぞ, the one every anime hero shouts, is not an invitation at all.

Learners usually meet this phrase backwards: they hear 行いくぞ! in an action scene, copy it, and then wonder why a coworker looks startled. The good news is that the whole family comes from one small idea, the volitional form, and once you see it the rest sorts itself out by tone.

The basics

How do you say "let's go" politely and casually?

Use 行いきましょう in polite speech and 行いこう in casual speech. Both mean "let's go" — an invitation that includes the listener.

行いきましょう。 — Let's go. (polite, safe with colleagues, teachers, strangers) 行いこう。 — Let's go. (casual, friends and family) 一緒いっしょに行いきましょう。 — Let's go together. (polite, friendly)

If you are not sure which to pick, 行いきましょう never sounds wrong. For choosing between the two registers in general, see our guide to when to switch between keigo and casual Japanese.

How do you make the volitional form (〜よう / 〜おう)?

The volitional form is the "let's / I'll" form of a verb. It is built on the dictionary form, and the method depends on the verb group.

Verb type Rule Example Volitional
う-verbs final u sound → o sound + う 行いく → 行ぎょうこう 行いこう
う-verbs same rule 飲のむ → 飲いんもう 飲のもう
る-verbs drop る, add よう 食たべる → 食たべよう 食たべよう
Irregular memorize 来くる → 来こよう (こよう) 来こよう
Irregular memorize する → しよう しよう

For う-verbs, the last kana moves from the u row to the o row: く→こ, む→も, す→そ, つ→と, ぬ→の, ぶ→ぼ, ぐ→ご, る→ろ, う→おう. Then you add う. It is a different system from the te-form, so don't mix up the endings.

ご飯はん、食たべよう。 — Let's eat. (casual, る-verb) 今日きょうは早はやく帰かえろう。 — Let's go home early today. (casual, う-verb 帰かえる)

The polite version is simpler: take the ます-stem and add ましょう. 行いく → 行いき → 行いきましょう. This works for every verb without exception.

What does 行いこうか add?

行いこうか is "shall we go?" — the か turns a flat "let's go" into a softer invitation that leaves the other person room to say no.

そろそろ行いこうか。 — Shall we get going? (casual, gentle, the person has a say) 行いきましょうか。 — Shall we go? (polite, offering, suggesting)

Use plain 行いこう when you have already decided, and 行いこうか when you are checking in. Between friends, the か version is the more considerate default.

How do you say "let's go" when you're leaving the house?

Say 出でかけよう ("let's head out") or 出発しゅっぱつ! ("departure!" — we're off). 行いこう is about going somewhere; 出でかけよう is about leaving where you are.

そろそろ出でかけよう。 — Let's head out soon. (casual, leaving home) よし、出発しゅっぱつ! — Okay, we're off! (cheerful, a parent or tour leader)

Beyond the basics

What does 行いくぞ mean, and is it an invitation?

行いくぞ means "I'm going!" or "here we go!" It is a declaration, not an invitation. The ぞ is a sentence-ending particle that pushes your own resolve at the listener, and it sounds masculine and forceful. The very similar 行いくぜ is the same idea with a cooler, more swaggering edge.

行いくぞ! — Here I go! (masculine, firing yourself up or warning an opponent) 行いくぜ! — Here we go! (masculine, cocky, a bit rock-and-roll) 行いくぞ、みんな! — Let's go, everyone! (a leader rallying a team — the ぞ announces that he is moving, and the team follows)

That last line is why learners think 行いくぞ means "let's go": in a group scene, announcing that you are going works as a rallying call, so everyone goes along. But grammatically you are still saying "I'm going." In shounen anime you will hear it right before a charge, a transformation, or a big jump.

What are さあ、行いこう and よし、行いくか?

These are the warm-up words that turn a plain verb into a "let's get moving" moment. さあ is "come on / now then" and よし is "okay, right" — both signal that the waiting is over.

さあ、行いこう。 — Come on, let's go. (casual, encouraging) よし、行いくか。 — Alright, let's head off. (casual, masculine, a self-nudge with か, like "well, shall I?")

行いくか with a falling tone is the "okay, time to go" you say mostly to yourself and whoever is next to you. It is relaxed, and common among men in casual speech.

What about レッツゴー?

レッツゴー is just "let's go" in English, written in katakana. It is fully understood, but it sounds playful, cheerful, or a little silly, like a parent leading a family outing or a mascot at an event.

それじゃ、レッツゴー! — Alright then, let's go! (playful, a bit goofy, kids' or event tone)

Use it for fun. Do not use it in a serious moment, and never to a boss unless the mood is clearly a joke.

How do you say "come on, let's go" when you're in a hurry?

Add the idea of speed: 早はやく行いこう ("let's go quickly") or the nudging ほら、行いくよ ("look, I'm going"). The sentence-final よ is what parents and friends use when they are pulling someone along.

早はやく行いこう、遅おくれるよ! — Let's hurry, we'll be late! (casual, urgent) ほら、行いくよ。 — Come on, we're going. (casual, a parent or friend dragging you along, よ = "I'm telling you")

This is really a sibling of "hurry up" — our post on hurry up in Japanese covers 急いそいで and 早はやく in detail.

Is 行いけ the same as "let's go"?

No. 行いけ is the plain imperative: "Go!" It tells someone else to go. 行いこう includes you. 行いけ is a command.

行いけ! — Go! (a command, shouted in a fight or a race, e.g. to a teammate or a thrown projectile) 行いこう! — Let's go! (we both go) 行いけ、みんな! — Go, everyone! (a leader sending the team ahead, without joining them)

In anime a character shouting 行いけ! at a robot or a teammate is sending them off. A character shouting 行いこう! is joining them. It is one vowel of difference and a big difference in meaning.

How do anime characters usually shout it?

The patterns are consistent. Heroes and fighters go with 行いくぞ / 行いくぜ, since they are announcing their own move. Friends heading out together say 行いこう or 行いこうよ. A calm senior character says 行いきましょう, and a kid or comic character may go レッツゴー!

みんな、行いくぞ! — Everyone, here we go! (a hero rallying his friends) 行いこうよ、ねえ、行いこうよ! — Come on, let's go, please, let's go! (casual, pleading, よ adds insistence) では、行いきましょうか。 — Well then, shall we go? (polite, a composed, dignified type)

Next time you watch something, listen for which ending each character picks. It tells you their gender image, their age, and their relationship to the people around them.

Does the spelling いこう vs いこ matter in texts?

In texts and chat, 行いこう is often written in hiragana as いこう, and in very casual messages it shrinks to いこ or いこー. They mean the same thing, "let's go."

ごはん、いこ! — Let's go eat! (very casual, text message) 明日あしたいこうよ。 — Let's go tomorrow! (casual, chat)

いこ is fine for close friends and unacceptable for a client's email. When in doubt, write the full 行いきましょう.

Common mistakes

  • Saying 行いくぞ to a boss or a teacher. It is a masculine declaration, not a polite invitation. Use 行いきましょう or 行いきましょうか.
  • Confusing 行いこう with 行いく? 行いく? with rising intonation asks "are you going?" 行いこう means "let's go." Same verb, different job: one is a question about the other person, the other is a joint plan.
  • Using 行いけ when you mean "let's go." 行いけ is "Go!" aimed at someone else. If you are going too, say 行いこう.
  • Using 行いこう with a stranger or an older person. The grammar is right but the register is off. Switch to 行いきましょう.
  • Building the volitional with the te-form. 行いって is not "let's go" by itself. The "let's" shape is 行いこう, not 行いって.
  • Writing いこ in an email. Fine in a chat with a friend, too casual for anything that looks like work.

The "let's go" ladder

Phrase Feel When to use it
行いきましょう Polite, safe Colleagues, teachers, new acquaintances
行いきましょうか Polite, softer Suggesting to someone you're not close with
行いこうか Casual, gentle Friends, checking in
行いこう / 行いこうよ Casual, direct Friends, family
行いくか Casual, masculine, self-nudge "Okay, time to go"
行いくぞ / 行いくぜ Masculine declaration Announcing your own move, hype
レッツゴー Playful, silly Fun outings, kids, jokes
行いけ Command "Go!" aimed at others

Practice

Build each answer before opening it. Questions 3 and 4, and 7 and 8, are pairs — watch what one small change does.

1. Say "Let's go" politely.

Show answer

行いきましょう — the ます-stem 行いき plus ましょう. It works for every verb and is safe with adults you should be polite to.

2. Say "Let's go" casually, to a friend.

Show answer

行いこう — 行いく is an う-verb, so the final く becomes こ and you add う.

3. Make the volitional of 食たべる.

Show answer

食たべよう — る-verbs drop る and add よう. This is the pair to question 4.

4. Make the volitional of 飲のむ.

Show answer

飲のもう — 飲のむ is an う-verb, so む becomes も and you add う. Compare with question 3: the group decides the rule.

5. What are the volitional forms of 来くる and する?

Show answer

来こよう (こよう) and しよう — both are irregular and have to be memorized.

6. You want to ask a friend "Shall we go?" softly. What do you say?

Show answer

行いこうか — the か turns the invitation into a gentle suggestion that leaves room for the friend to answer.

7. A hero announces "Here I go!" before a charge. Which ending does he use: 行いこう or 行いくぞ?

Show answer

行いくぞ — ぞ is a masculine declaration of your own move. It is not an invitation, though a group may follow it. This is the pair to question 8.

8. Your coworker is ready to leave and you want to suggest going together. Can you say 行いくぞ?

Show answer

No — say 行いきましょう (or 行いきましょうか). 行いくぞ is a blunt, masculine declaration and sounds rude to someone you should be polite to.

9. What is the difference between 行いけ and 行いこう?

Show answer

行いけ is a command ("Go!"), 行いこう includes you ("Let's go") — 行いけ sends someone off, 行いこう goes along with them.

10. A parent says "Come on, we're going!" while pulling a child along. Which sentence fits: ほら、行いくよ or 行いきましょう?

Show answer

ほら、行いくよ — ほら gets attention, and the よ is the casual nudge parents and friends use. 行いきましょう is too polite for that scene.

Use a trial lesson to invite a friend with 行いこう and a boss with 行いきましょう, and save 行いくぞ for your best anime-hero voice.

FAQ

Is 行いこう polite? No. 行いこう is casual, for friends and family. For adults you are not close to, use 行いきましょう.

Can I say 行いくぞ to a friend? Yes, if you are announcing your own move or hyping a group, and if you are comfortable sounding masculine. It is not a polite invitation, and many women use 行いくよ instead for a similar "we're going now" feeling.

What is the difference between 行いこう and 行いこうか? 行いこう states a plan you have already made. 行いこうか asks "shall we?" and leaves room for the other person to disagree.

Does 行いきましょう work for every verb, like 食たべましょう and 飲のみましょう? Yes. Take the ます-stem and add ましょう: 食たべます → 食たべましょう, 飲のみます → 飲のみましょう. It has no exceptions, which makes it the easiest "let's" form to learn first.

Is レッツゴー used in real life? Yes, but mostly as a playful, cheerful phrase. It fits an outing, a festival, or a joke. For ordinary invitations, use 行いこう or 行いきましょう.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab, and each line becomes one card.

行く	いく — to go
行こう	いこう — let's go (casual)
行きましょう	いきましょう — let's go (polite)
行こうか	いこうか — shall we go?
行くぞ	いくぞ — here I go! (masculine declaration)
行くぜ	いくぜ — here we go! (cocky, masculine)
行け	いけ — go! (command)
出かける	でかける — to go out, to leave the house
出発	しゅっぱつ — departure
早く	はやく — quickly
一緒に	いっしょに — together
帰る	かえる — to go home
食べる	たべる — to eat
飲む	のむ — to drink
来る	くる — to come
する	する — to do
さあ	さあ — come on, now then
よし	よし — okay, right
レッツゴー	レッツゴー — let's go (loanword)
ほら	ほら — look, come on

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime, so most of the example sentences on this blog come from the kinds of lines I hear again and again in shows and in lessons. For practice with feedback, Book a trial lesson · $13, or work through Japanese practice exercises first.

Sources: the author's own lessons and standard reference grammars.

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