Technical Japanese #06 — Shop-Floor Action Verbs: Tighten, Loosen, Adjust, Check and Replace
In a Japanese plant the noun tells you what, but the verb tells you what to do. Hear 締める (tighten) when it was 緩める (loosen) and you damage the part or cause an accident. This post collects the twenty action verbs you meet most often on a 作業票 and in a team leader's spoken instruction. Learn them as whole phrases and you act correctly the first time.
Core action verbs on the floor
Use the かな column to say the word, and keep the kanji so you can read the sheet. Learn the example sentence with the verb — that is what makes it usable.
| Japanese | Reading | Meaning | Example |
|---|
| 締める | しめる shimeru | to tighten | ボルトを締める |
| 緩める | ゆるめる yurumeru | to loosen | ナットを緩める |
| 調整する | ちょうせい chōsei suru | to adjust | 圧力を調整する |
| 確認する | かくにん kakunin suru | to confirm | 数値を確認する |
| 交換する | こうかん kōkan suru | to replace | フィルターを交換する |
| 点検する | てんけん tenken suru | to inspect | 設備を点検する |
| 押す | おす osu | to push | ボタンを押す |
| 引く | ひく hiku | to pull | レバーを引く |
| 回す | まわす mawasu | to turn | ハンドルを回す |
| 外す | はずす hazusu | to remove | カバーを外す |
| 取り付ける | とりつける toritsukeru | to fit, to install | センサーを取り付ける |
| 止める | とめる tomeru | to stop something | 機械を止める |
| 起動する | きどう kidō suru | to start up | ポンプを起動する |
| 清掃する | せいそう seisō suru | to clean | 現場を清掃する |
| 記入する | きにゅう kinyū suru | to fill in | 日報に記入する |
| 測定する | そくてい sokutei suru | to measure | 寸法を測定する |
| 組み立てる | くみたてる kumitateru | to assemble | 部品を組み立てる |
| 分解する | ぶんかい bunkai suru | to disassemble | ユニットを分解する |
| 供給する | きょうきゅう kyōkyū suru | to supply, to feed | 材料を供給する |
| 切る | きる kiru | to cut off | 電源を切る |
Nearly all of them take the particle を: [noun] を [verb]. Hold that frame and you can build any number of sentences.
Three endings to catch immediately — they carry the safety
The kanji stem gives the action; the ending gives the context — a request, a prohibition, or a completed step.
| Ending | Meaning | Example | What you do |
|---|
| 〜てください | please do this | 確認してください | Do it |
| 〜ないでください | please do not — a safety prohibition | 触らないでください | Stop, do not touch |
| 〜ました / 〜ています | done / in progress | 交換しました / 運転しています | Note the state |
Sentences by situation
① You are asked to do something
- ボルトを締めてください。 — Please tighten the bolt.
- フィルターを交換してください。 — Please replace the filter.
- スイッチを押す前に、確認してください。 — Before you press the switch, confirm.
② You are being stopped — this is a safety signal
- カバーを外さないでください。 — Do not remove the cover.
- 電源を切らないでください。 — Do not cut the power.
- 運転中は触らないでください。 — Do not touch it while it is running.
③ You are reporting that something is done
- 点検が終わりました。 — The inspection is finished.
- 部品を交換しました。 — I replaced the part.
- 現在、測定しています。 — I am measuring now.
Intransitive is not transitive — say the wrong one and you report the wrong thing
Japanese separates "it happened by itself" (自動詞, with が) from "someone made it happen" (他動詞, with を). Both translate as "stop", but they are completely different reports.
| Intransitive — が | Transitive — を | Meaning |
|---|
| 止まる (tomaru) the machine stopped by itself | 止める (tomeru) I stopped the machine | stopping |
| 動く (ugoku) the machine runs | 動かす (ugokasu) I run it | moving |
| 開く (aku) the door opens | 開ける (akeru) I open it | opening |
| 閉まる (shimaru) the door closes | 閉める (shimeru) I close it | closing |
| 付く (tsuku) the lamp comes on | 付ける (tsukeru) I switch it on | switching on |
モーターが止まりました means the motor stopped on its own — that is a fault report. モーターを止めました means you stopped it — that is an action report. A team leader reacts very differently to the two. The shortcut: hear が and it happened by itself; hear を and a person did it.
Four levels of instruction — who is speaking, and how urgent
| Form | Example | Tone | Where you hear it |
|---|
| 〜てください | 確認してください | Standard polite | On paperwork, from your team leader |
| 〜て (clipped) | 確認して | Quick, familiar | From a colleague, when time is short |
| 〜なさい | 確認しなさい | A senior correcting you | Training, correcting a mistake |
| 〜てはいけない | 触ってはいけない | Absolute prohibition | Safety rules |
In an emergency people shout the shortest form there is, so you have to react to the verb stem alone: 止めて！ (stop it), 離れて！ (get back), 押さないで！ (don't press it).
Mistakes to avoid
| Confusion | Why it is dangerous |
|---|
| 締める (tighten) against 緩める (loosen) | Exact opposites: getting it wrong damages the part or injures someone. Both carry the 糸 radical, but 緩 means loose and slow |
| Dropping the 〜ないで ending | Hearing only the stem 触る and missing 触らないで reverses a safety instruction |
| Treating 調整 (adjust) as 修理 (repair) | Adjusting is bringing something to the right setting; repairing is fixing a failure. Report the wrong one and the machine's condition is misunderstood |
| Treating 確認 (confirm) as 点検 (inspect) | 確認 is a quick check on the spot; 点検 is a scheduled procedure with a record |
Hear it, then act — quick self-check
Read the Japanese and decide what you would do. Answers below.
- バルブを閉めてください。
- カバーを外さないでください。
- モーターが止まりました。
- 圧力を調整してください。
- 電源を切って、点検してください。
<details><summary>Answers</summary>
- Close the valve (閉める is to close).
- Do not remove the cover — a safety prohibition.
- A report: the motor stopped by itself (が), so it may be a fault and the cause needs checking.
- Adjust the pressure to the correct value.
- Cut the power, then carry out the inspection — two 〜て actions in sequence.
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Quick recall
- The frame:
[noun] を [verb]. Remember を and you can assemble a hundred sentences. - Three endings: 〜てください (please do) · 〜ないでください (do not — safety) · 〜ました (done).
- Opposite pairs: 締める and 緩める, 押す and 引く, 取り付ける and 外す. Learn them in pairs so you cannot swap them.
- が is not を: 止まる (it stopped, が) is a different report from 止める (I stopped it, を).
- In an emergency the short form is all you get — 止めて, 離れて — so drill the stems.
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Next in the Technical Japanese series: how to ask again when you did not understand · the 100 shop-floor kanji · maintenance vocabulary (保全).
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