Technical Japanese #23 — Reading a Japanese Specification Sheet (仕様書): Structure and Risk Points
The drawing gives you the shape. The 仕様書 gives you the requirement: operating conditions, the standards that apply, acceptance conditions, delivery. Miss one line of it and a part that matches the drawing perfectly can still be rejected. This post walks through the usual structure and the places where people get caught.
Core vocabulary of the 仕様書
| Japanese | Reading | Meaning | In the spec | Note |
|---|
| 仕様書 | しようしょ shiyōsho | specification document | 仕様書に従う | The document itself |
| 仕様 | しよう shiyō | specification | 仕様を確認 | A single spec item |
| 要求 | ようきゅう yōkyū | requirement | 要求事項 | What is being asked for |
| 条件 | じょうけん jōken | condition | 使用条件 | Operating condition |
| 適用範囲 | てきようはんい tekiyō han'i | scope | 適用範囲を明記 | Scope of application |
| 規格 | きかく kikaku | standard | JIS規格 | Standard |
| 準拠 | じゅんきょ junkyo | in compliance with | JISに準拠 | Complies with |
| 検収条件 | けんしゅうじょうけん kenshū jōken | acceptance condition | 検収条件を満たす | Acceptance |
| 環境条件 | かんきょうじょうけん kankyō jōken | environmental condition | Temperature, humidity | Environment |
| 定格 | ていかく teikaku | rated | 定格電圧 | Rated value |
| 最大 | さいだい saidai | maximum | 最大荷重 | Max |
| 最小 | さいしょう saishō | minimum | 最小値 | Min |
| 以上 / 以下 | いじょう / いか ijō / ika | at least / at most | 10以上 | Includes the figure |
| 未満 / 超 | みまん / ちょう miman / chō | under / over | 10未満 | Excludes the figure |
| 添付 | てんぷ tenpu | attached | 図面添付 | Attached document |
| 備考 | びこう bikō | remarks | 備考欄 | Remarks column |
| 保証 | ほしょう hoshō | warranty | 保証期間 | Warranty |
The usual structure of a 仕様書
- 適用範囲 — what product or process this specification covers.
- 引用規格 — the JIS, ISO or customer standards being invoked.
- 用語の定義 — read this carefully: a word may be given a narrow local meaning.
- 仕様 / 要求事項 — the table of rated values, tolerances and materials.
- 試験・検査方法 — how it is measured and what counts as a pass.
- 検収条件 — the basis on which the customer accepts the goods.
- 納入・梱包 and 備考 — delivery, packing and remarks.
Where it goes wrong most often
- 以上/以下 against 未満/超.
10以上 includes 10; 10未満 excludes it. Get it backwards and your criterion is off by one boundary. - 定格 is a rated value, not necessarily the absolute ceiling — a separate 最大 may be given.
- 準拠 against 参考. 「JISに準拠」 is mandatory; 参考 is for reference only.
- 検収条件. A part that meets the 仕様 can still fail 検収 if the required certificate or test report is missing.
Phrases by situation
Confirming the requirement
- この仕様書の適用範囲を教えてください。 — What does this specification cover?
- 検収条件は何ですか。 — What are the acceptance conditions?
- この値は最大ですか、定格ですか。 — Is this value a maximum or a rating?
Clearing up an ambiguity
- 「以上」は10を含みますか。 — Does 以上 include 10?
Mistakes to avoid
| Mistake | Why it hurts |
|---|
| Reading the value table and skipping 試験・検査方法 | You hit the number but measure it the wrong way, and the result is not recognised |
| Treating every 規格 as "for reference" | You drop a requirement the customer considers mandatory |
| Not cross-checking the 仕様書 against the 図面 | When they conflict, 設計 decides which governs — never choose for yourself |
Read it, then act — quick self-check
The spec says: 「引張強度 400MPa以上、JIS Z 2241に準拠して試験すること。」
<details><summary>Answer</summary>Tensile strength of 400 MPa or more (以上 includes 400), and the test must follow JIS Z 2241 (準拠 is mandatory). Hitting the number while testing to another method still fails.</details>
The engineer says: 「図面と仕様書で寸法が違う。設計に確認して。」
<details><summary>Answer</summary>The drawing and the specification disagree on a dimension. Ask 設計 which one governs. Do not pick one yourself.</details>
How MINATA helps
Do you have a Japanese 仕様書 whose requirements, standards and acceptance conditions must be read correctly before you commit? MINATA breaks the specification down, cross-checks it against the drawing and settles the ambiguities with the Japanese side before production starts. See our Japan–Vietnam projects or engineering and production services.
View all MINATA technical articles