Technical Japanese #04 — 100 High-Frequency Kanji for the Japanese Factory Floor
"2,136 common-use kanji" sounds like a wall. Inside a factory the characters that come back day after day are far fewer — a core of about 100 covers most of what appears on drawings, machining notes, process sheets and signs. Learning them by theme works several times better than learning them spread thin. This is that core set, laid out as a lookup map.
The reading column gives the on or kun reading you will actually hear on the floor. The goal is recognition and meaning in context, not calligraphy.
Group 1 — Machining and operations (加工・作業)
| Kanji | Reading | Meaning |
|---|
| 加工 | kakō | machining |
| 研磨 | kenma | grinding, polishing |
| 工程 | kōtei | process step |
| 曲げ | mage | bending |
| 作業 | sagyō | task, operation |
| 穴 | ana | hole |
| 組立 | kumitate | assembly |
| 面取り | mentori | chamfer |
| 溶接 | yōsetsu | welding |
| 切削 | sessaku | cutting, machining |
Group 2 — Inspection and quality (検査・品質)
| Kanji | Reading | Meaning |
|---|
| 検査 | kensa | inspection |
| 公差 | kōsa | tolerance |
| 品質 | hinshitsu | quality |
| 測定 | sokutei | measurement |
| 良品 | ryōhin | good part |
| 基準 | kijun | reference, datum |
| 不良 | furyō | defect |
| 確認 | kakunin | confirmation |
| 寸法 | sunpō | dimension |
| 合格 | gōkaku | pass |
Group 3 — Equipment and tools (設備・工具)
| Kanji | Reading | Meaning |
|---|
| 設備 | setsubi | equipment (general) |
| 材料 | zairyō | material |
| 装置 | sōchi | functional machine |
| 金型 | kanagata | die, mould |
| 治具 | jigu | jig, fixture |
| 電源 | dengen | power supply |
| 工具 | kōgu | tool |
| 配線 | haisen | wiring |
| 部品 | buhin | part, component |
| 交換 | kōkan | replacement |
Group 4 — Production and management (製造・管理)
| Kanji | Reading | Meaning |
|---|
| 製造 | seizō | manufacturing |
| 在庫 | zaiko | stock, inventory |
| 生産 | seisan | production |
| 納期 | nōki | delivery date |
| 技術 | gijutsu | engineering, technology |
| 段取り | dandori | set-up, changeover |
| 管理 | kanri | control, management |
| 稼働 | kadō | in operation |
| 数量 | sūryō | quantity |
| 出荷 | shukka | shipping |
Group 5 — Safety and maintenance (安全・保全)
| Kanji | Reading | Meaning |
|---|
| 安全 | anzen | safety |
| 点検 | tenken | scheduled inspection |
| 危険 | kiken | danger |
| 故障 | koshō | breakdown |
| 注意 | chūi | caution |
| 停止 | teishi | stop |
| 禁止 | kinshi | prohibited |
| 異常 | ijō | abnormality |
| 保全 | hozen | maintenance |
| 復旧 | fukkyū | recovery, restoration |
| 予防保全 | yobō hozen | preventive maintenance |
| 日常点検 | nichijō tenken | daily check |
| 部品交換 | buhin kōkan | parts replacement |
| 点検項目 | tenken kōmoku | inspection item |
| 周期 | shūki | interval |
| 保全計画 | hozen keikaku | maintenance plan |
Group 6 — Instructions and direction (指示・方向)
| Kanji | Reading | Meaning |
|---|
| 上/下 | ue/shita | up / down |
| 調整 | chōsei | adjustment |
| 左/右 | hidari/migi | left / right |
| 取付 | toritsuke | fitting, installation |
| 前/後 | mae/ushiro | front / back |
| 取外 | torihazushi | removal |
| 締める | shimeru | to tighten |
| 開/閉 | kai/hei | open / close |
| 緩める | yurumeru | to loosen |
| 押す/引く | osu/hiku | push / pull |
Group 7 — Drawings and tolerance (図面・公差)
| Kanji | Reading | Meaning |
|---|
| 図面 | zumen | drawing |
| 幾何公差 | kika kōsa | geometric tolerance |
| 平面度 | heimendo | flatness |
| 真円度 | shin'endo | roundness |
| 同軸度 | dōjikudo | concentricity |
| 平行度 | heikōdo | parallelism |
| 直角度 | chokkakudo | squareness |
| 表面粗さ | hyōmen arasa | surface roughness |
| 直径 | chokkei | diameter |
| 半径 | hankei | radius |
| 尺度 | shakudo | scale |
| 表題欄 | hyōdairan | title block |
| 注記 | chūki | notes |
| 詳細図 | shōsaizu | detail view |
Group 8 — Measurement and error (測定・誤差)
| Kanji | Reading | Meaning |
|---|
| 測定値 | sokuteichi | measured value |
| 校正 | kōsei | calibration |
| 誤差 | gosa | error, deviation |
| 重量 | jūryō | weight |
| 温度 | ondo | temperature |
| 度 | do | degree (angle) |
Group 9 — Materials and ordering (資材・発注)
| Kanji | Reading | Meaning |
|---|
| 消耗品 | shōmōhin | consumables |
| 発注 | hatchū | placing an order |
| 発注書 | hatchūsho | purchase order |
| 仕入先 | shiiresaki | supplier |
| 購買 | kōbai | purchasing |
| 品番 | hinban | part number |
| 品名 | hinmei | item name |
| 補充 | hojū | replenishment |
Group 10 — Electrical and signals (電気・信号)
| Kanji | Reading | Meaning |
|---|
| 電源 | dengen | power supply |
| 配線 | haisen | wiring |
| 端子 | tanshi | terminal |
| 電磁弁 | denjiben | solenoid valve |
| 信号 | shingō | signal |
| 入出力 | nyūshutsuryoku | input/output |
Katakana — the other half of the drawing
| Katakana | Reading | Meaning |
|---|
| モーター | mōtā | motor |
| センサー | sensā | sensor |
| スイッチ | suitchi | switch |
| ボルト | boruto | bolt |
| ベアリング | bearingu | bearing |
| ユニット | yunitto | unit, assembly |
| ライン | rain | line |
| データ | dēta | data |
Three ways to guess a character you have not met
- On (音) versus kun (訓) readings. A compound of two kanji almost always takes the on reading (加工 kakō, 検査 kensa); a verb with a kana tail takes the kun reading (締める shimeru). That one rule gets you the pronunciation of most new words.
- Radicals (部首). 金 means metal, so 鉄 is iron, 鋼 is steel, 錆 is rust. 手 and 扌 mean handling: 押 push, 締 tighten. 車 means motion: 転 rotate, 軸 shaft.
- Compound logic. Once you know 加 (add) and 工 (work) you have 加工; 工 plus 程 gives 工程; 工 plus 具 gives 工具. One character links to many words, and the 100 stop being a list and become a network.
Read a real line with the core set
「加工後、バリ取り、寸法検査、合格品のみ出荷」 means: after machining, deburr, inspect the dimensions, ship only the parts that passed. The whole line sits inside the 100-kanji core.
Mistakes to avoid
| Mistake | Why it hurts |
|---|
| Trying to learn 2,000 kanji before starting work | You do not need them — the 100-character core is enough to work and to build momentum |
| Memorising the meaning but dropping the reading | If you cannot say it, you cannot ask about it or discuss it |
| Studying characters away from context | Anchor every character to a real drawing or a real sentence |
| Avoiding compounds | Most terms are two-kanji compounds — know the parts and you can infer the whole |
Read it, then act — quick self-check
What do these lines mean?
- 検査後、合格品のみ
- 危険・立入禁止
- 加工後、寸法確認
- 故障時は停止
<details><summary>Answers</summary>
- After inspection, passed parts only.
- Danger — no entry.
- After machining, confirm the dimensions.
- In case of a breakdown, stop the machine.
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Want a thicker reference with kana readings and real field examples? Download the free shop-floor Japanese lookup table — 201 terms across 12 departments.
Quick recall
- Start with the group your own department uses; ten characters a day, recognition first, writing later.
- Two-kanji compounds take the on reading; verbs with a kana tail take the kun reading.
- You need the 100 kanji plus fluent katakana before a drawing reads end to end.
Do you have Japanese drawings, notes or technical documents that have to be understood before work can start? Instead of looking up character by character, MINATA can take on reading and translating Japanese drawings and documents, then designing and machining to Japanese standards. See our Japan–Vietnam services and projects we have delivered.
Next in the series: reading dimensions on a drawing (寸法・φ・R・C) · technical katakana · 生産技術 and vocabulary by department.
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