行く: The te-form Exception | Japanese Grammar

行く（いく, "to go"）is one of the first verbs you learn and one of the most frequent in the language — and it hides the single most important irregularity in the whole 五段 (godan) system. Everywhere except one place it is a textbook-regular -く verb: 行かない, 行きます, 行ける, 行こう all behave exactly like 書く（かく）. But in the te-form and past, 行く refuses the -く → -いて change its class demands and takes the doubling っ instead: 行って／行った, never the ×行いて／×行いた that the pattern predicts. This page is a targeted patch on that one cell — not a full paradigm.

Everything else is perfectly regular

Before the exception, fix the rule in place: outside the te/ta cells, 行く walks the k-column like any other -く verb. There is nothing to memorize here — just copy 書く.

Form	行く	Reading
Dictionary	行く	iku
Polite 〜ます	行きます	ikimasu
Plain negative	行かない	ikanai
Polite negative	行きません	ikimasen
Potential (can go)	行ける	ikeru
Volitional (let's go)	行こう	ikō
Conditional 〜ば	行けば	ikeba
Imperative	行け	ike
Passive / Causative	行かれる／行かせる	ikareru / ikaseru

毎朝、電車で会社に行きます。

maiasa, densha de kaisha ni ikimasu

Every morning I go to work by train.

今日は疲れたから、ジムには行かない。

kyō wa tsukareta kara, jimu ni wa ikanai

I'm tired today, so I'm not going to the gym.

もう時間だ、そろそろ行こう。

mō jikan da, sorosoro ikō

It's time — let's get going.

Every one of those is the plain -く pattern with the k intact. If 行く stopped there, it would need no page of its own.

The exception: 行って／行った, not ×行いて／ ×行いた

The regular -く verb softens く to the vowel い before て／た — the い-音便 (イおんびん): 書く → 書いて, 聞く → 聞いて, 歩く → 歩いて. 行く is the one -く verb in the language that does not do this. Instead it takes the small-っ 促音便 (そくおんびん) — the same doubling you see in the -つ and -る verbs — giving 行って and 行った.

Cell	Regular -く (書く)	行く does this instead
Te-form 〜て	書いて (kaite)	行って (itte)
Past 〜た	書いた (kaita)	行った (itta)
Conditional 〜たら	書いたら (kaitara)	行ったら (ittara)
Representative 〜たり	書いたり (kaitari)	行ったり (ittari)

The doubling ripples through everything built on the te/ta stem — the past, the たら-conditional, the 〜たり list form — so all four cells switch together. Learn the te-form 行って and the rest follow.

週末、友達と映画を見に行った。

shūmatsu, tomodachi to eiga o mi ni itta

I went to see a movie with a friend over the weekend.

銀行に行ってから、郵便局にも寄った。

ginkō ni itte kara, yūbinkyoku ni mo yotta

I went to the bank and then also stopped by the post office.

ちょっと病院に行ったら、二時間も待たされた。

chotto byōin ni ittara, nijikan mo matasareta

I just popped to the clinic and got made to wait two whole hours.

Why it breaks — and what to do about it

There is no live rule that produces 行って from 行く; you cannot derive it. Historically both a regular いきて and the euphonic いって circulated, and for this one ultra-frequent verb the っ-form simply won. The honest instruction is the same one English gives a child for went: memorize it as a fixed shape and stop trying to build it. Because "to go" appears in nearly every conversation, the form will lodge itself fast.

💡

Three strings sound close but only one is right in modern Japanese: ✅ 行って（itte, the correct 促音便）; ❌ 行いて（iite — the wrong form learners build by copying 書いて）; and 行きて（ikite — the genuine classical / literary te-form you still meet in poetry and old song lyrics, but never in speech). The error to kill is the middle one.

Note also that 行く carries a second, literary reading ゆく (yuku), heard in set phrases and lyrics (過ぎ行く, "to pass by"). Even under that reading the te-form is still 行って — there is no ×ゆいて.

The 行った／言った homophone

Here is the trap that catches even intermediate learners' ears. 行って／行った read itte / itta — sound-for-sound identical to 言って／言った, the te-form and past of 言う（いう, "to say"）. Two of the most common verbs in the language collapse into the same sound, and only the kanji and the context tell them apart.

娘は元気に「行ってきます」と言って出かけた。

musume wa genki ni ittekimasu to itte dekaketa

My daughter cheerfully said 'I'm off!' and headed out.

That one sentence carries both: 行ってきます ("I'm off," from 行く) and 言って ("said," from 言う), both pronounced itte.

はっきり言って、その案には反対だ。

hakkiri itte, sono an ni wa hantai da

To put it bluntly, I'm against that proposal. (言って, not 行って)

駅まで歩いて行って、そこから電車に乗った。

eki made aruite itte, soko kara densha ni notta

I walked to the station and from there took the train. (行って)

A third verb joins the club in casual speech: 要る（いる, "to need"）is also 五段, so its past is 要った — again itta. Kanji keep them separate on the page; in speech you lean entirely on context.

Compounds inherit the exception

Any verb that ends in 〜行く carries the irregularity with it. The productive auxiliary 〜ていく ("do and go / go off doing") and the lexical compounds 出て行く（でていく, "leave"）, 連れて行く（つれていく, "take someone along"）, 持って行く（もっていく, "take something along"）all form their te/ta with って.

この荷物、会議室まで持っていってくれる?

kono nimotsu, kaigishitsu made motte itte kureru

Could you take this luggage to the meeting room (for me)?

彼は何も言わずに部屋を出て行った。

kare wa nani mo iwazu ni heya o dete itta

He left the room without saying a word.

準備は全部うまくいって、無事に終わった。

junbi wa zenbu umaku itte, buji ni owatta

The preparations all went smoothly and it wrapped up without a hitch. (うまくいく → うまくいって)

How this differs from English

English hides an identical fact in plain sight: go takes the irregular past went — a completely unrelated stem — while every regular verb just adds -ed. Japanese is gentler. 行く keeps its own stem and only bends the linking cell (て／た), and it bends it toward a pattern the language already uses everywhere else (って). So the mental move is exactly the one you made as a child: treat "go" as the verb whose connecting form you simply know by heart, and treat the other eight -く verbs as fully predictable. For the full map of which endings soften to いて, いで, って, or んで, see the te/ta sound-change chart and the roundup of irregular te-form verbs.

Common mistakes

❌ 昨日、京都に行いた。

Incorrect — 行く takes the 促音便, giving 行った; ×行いた copies the wrong 書いた pattern.

✅ 昨日、京都に行った。

kinō, Kyōto ni itta

Yesterday I went to Kyoto.

❌ 図書館に行いてください。

Incorrect — the te-form is 行って, not ×行いて.

✅ 図書館に行ってください。

toshokan ni itte kudasai

Please go to the library.

❌ 毎日この道を歩って通う。

Over-correction — only 行く is irregular; 歩く is a normal -く verb → 歩いて.

✅ 毎日この道を歩いて通う。

mainichi kono michi o aruite kayou

I walk this route to and from work every day.

❌ ちょっとそこまで行きて、すぐ戻る。

Incorrect — you can't leave the ます-stem 行き; the te-form is the 促音便行って.

✅ ちょっとそこまで行って、すぐ戻る。

chotto soko made itte, sugu modoru

I'll just go over there and come right back.

The two live errors pull in opposite directions: applying the regular いて to 行く (giving ×行いて) and applying 行く's exceptional って to a regular verb (giving ×歩って). Fix both with one fact — the irregularity is exactly one verb wide.

Key takeaways

行く is a fully regular 五段 -く verb in every cell except the te-form and past.
Te-form / past = 行って／行った (促音便, small っ), never the ×行いて／×行いた its class predicts — the doubling also carries into 行ったら and 行ったり.
It is the single high-frequency irregular in the godan te-system; memorize it like English went, not by rule.
行って／行った are homophones of 言って／言った (from 言う) — kanji and context separate them.
Compounds inherit it: 持っていく → 持っていって, 出て行く → 出て行った, うまくいく → うまくいって.
Don't over-correct: every other -く verb (書く, 聞く, 歩く, 働く…) is regular いて.

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