“moshiku wa・aruiwa・matawa”: Or (distinguishing three “or”s) [JLPT N1]

Content by NTJ Kuma · Nihongo to Japan editorial team · Updated July 27, 2026

Comparing the formality of three ways to say “or”

「電話もしくはメールで／現金または カード」 — three ‘or's and their formality

To say “A or B” but unsure which “or” to use — 「ご連絡は電話もしくはメールで」「お支払いは現金またはカード」 — 「もしくは・または・あるいは」 are all “or,” differing in formality and subtle feel. This guide clarifies the division of labor among the three (formality, the legal hierarchy, あるいは's conjecture sense) and contrasts them with the colloquial 「か.」

Core: three ‘or's, differing in formality and subtle feel

All three express “or, A or B,” differing in formality and feel:

① または = or (general, written, the commonest “or”):

• お支払いは、現金またはクレジットカードでお願いします (please pay with cash or credit card).

② もしくは = or (more formal, written, legal; often for a broader range or hierarchical options):

• 本人もしくは代理人が手続きを行う (the person themselves or a proxy carries out the procedure).

③ あるいは = or, or else (written; besides “or,” can also express the conjecture “perhaps”):

• 徒歩あるいは自転車で通勤する (commute on foot or by bicycle).
• あるいは、彼はもう知っているのかもしれない (perhaps he already knows).

Feel: the formality is roughly “あるいは／もしくは (more formal, written) ＞ または (general, written) ＞ か (most colloquial).” Also, 「あるいは」 can, besides “or,” stand alone to express the conjecture “perhaps, maybe.” All correspond to “or.”

Attachment rules

See it in context

• 参加の可否を、明日または明後日までにお知らせください。(Please let us know whether you'll attend by tomorrow or the day after.)
• 会員証もしくは身分証明書をご提示ください。(Please present your membership card or ID.)
• この問題は、話し合いあるいは投票で決めよう。(Let's decide this by discussion or a vote.)
• 彼は忙しいのだろう。あるいは、忘れているだけかもしれない。(He must be busy. Or perhaps he's simply forgotten.)
• 電車かバスで行けば間に合う。(You'll make it if you go by train or bus.) — colloquial

⚠️ Where learners slip up

① All three are ‘or,' differing in formality: か (colloquial) ＜ または (general) ＜ もしくは／あるいは (formal). This is the set's core distinction. The four “or”s differ in formality: 「か」 = most colloquial (everyday speech): コーヒーかお茶 (coffee or tea). 「または」 = general, written (the commonest “or,” used in formal documents and notices): 現金またはカード. 「もしくは」 = more formal, written, legal (more formal than または): 本人もしくは代理人. 「あるいは」 = written (more refined, can also express conjecture): 徒歩あるいは自転車. Test: everyday colloquial “A or B” → か; general writing／formal documents → または (most general); more formal／legal documents → もしくは; refined writing／or expressing conjecture → あるいは. Using the wrong one isn't ungrammatical, but the register clashes (「もしくは」 in casual conversation sounds too stiff; 「か」 in a formal contract sounds too casual).

② ⭐「あるいは」 can also express the conjecture ‘perhaps, maybe.' This is a use unique to 「あるいは,」 which the other two lack. Besides being “or” (joining two options), 「あるいは」 can stand alone at the sentence head to express the conjecture “perhaps, maybe”: あるいは、彼はもう帰ったかもしれない (perhaps he's already gone home), あるいはうまくいくかもしれない (maybe it'll go well). This “perhaps” use, 「または」「もしくは」 lack (they can only be “or”). So on seeing sentence-head 「あるいは〜かもしれない,」 it's mostly the conjecture “perhaps ～,” not “or.” Test: 「あるいは」 at the sentence head, followed by 「かもしれない」 etc. → “perhaps, maybe” (conjecture); 「あるいは」 in the middle of “A あるいは B” → “or” (options).

③ In legal documents, 「または」 for the major category, 「もしくは」 for the minor (advanced). This is an advanced division of labor between 「または」 and 「もしくは」 in rigorous legal／official documents. When options have a hierarchy (major, minor), the major category uses 「または,」 the minor 「もしくは」 — e.g. in a writing like 「東京都もしくは神奈川県、または千葉県,」 same-level minor items are joined with 「もしくは,」 and the largest division with 「または.」 This is the rigorous usage of legal text; general writing needn't distinguish this finely (everyday just uses 「または」). But if you see 「もしくは」 and 「または」 used together in a law／contract, it's distinguishing “minor (もしくは)” from “major (または).” Test: general writing “A or B” just uses 「または」; only in rigorous legal／official documents with hierarchical options do you distinguish “もしくは (minor)／または (major).” This is an advanced point occasionally tested at N1 — remember “in law: minor もしくは, major または.”

🔄 Compare: または／もしくは／あるいは／か

💡 Quick takeaway

「もしくは・または・あるいは」 are all “or” — three points: ① they differ in formality — か (colloquial) ＜ または (general written, commonest) ＜ もしくは／あるいは (formal written); ②⭐「あるいは」 can also express the conjecture “perhaps” (あるいは〜かもしれない), unique to it; ③ in legal documents, 「または」 for the major, 「もしくは」 for the minor category (advanced). This set is a practical register distinction — everyday chat uses 「か」 (電車かバス), general writing／notices use 「または」 (現金またはカード), formal contracts use 「もしくは,」 refined writing or conjecture uses 「あるいは.」 To pick the right “or,” first gauge the occasion's formality: the more formal → the more もしくは／あるいは／または; the more colloquial → the more か. (Remember 「あるいは」's hidden “perhaps” use.)

❓ Questions you might have

Q: What's the difference between 「または」 and 「もしくは」? Both ‘or'?

The difference is ‘formality' and the ‘hierarchy division' in legal documents. 「または」 = or (general, written, the commonest, most neutral “or”): it's the most general, common “or,” suited to general writing, formal documents, notices, somewhat-formal everyday settings, neutral and un-stiff: 現金またはカードでお支払いください (please pay with cash or card), 月曜日または火曜日に伺います (I'll visit Monday or Tuesday), A案またはB案から選ぶ (choose from plan A or plan B). It's the standard written phrasing of “or,” and in the vast majority of cases 「または」 is right. 「もしくは」 = or (more formal, written, legal, more formal than または): it's more formal, more written, more legal／official than 「または,」 less used in everyday life, mostly in formal contracts, regulations, legal text: 本人もしくはその代理人 (the person themselves or their proxy — legal language), 書面もしくは口頭で (in writing or orally). Difference ① (formality): 「または」 general (used in general writing); 「もしくは」 more formal (legal, formal documents). Difference ② (legal hierarchy): in rigorous legal text, when options have a major／minor hierarchy, the minor uses 「もしくは,」 the major 「または」 (e.g. 「A もしくは B、または C」 — A and B are the same minor group joined by もしくは, then joined with C, a major category, by または). This is the rigorous legal usage; general writing needn't distinguish. Test: general writing “A or B” → または (most general, always right); a formal contract／law, wanting more formality → もしくは; legal text with a hierarchy → minor もしくは, major または. In practice, everyday and general writing 「または」 suffices, and 「もしくは」 is mostly for formal, legal settings.

Q: Besides ‘or,' does 「あるいは」 have another meaning?

Yes — 「あるいは」 can also express the conjecture “perhaps, maybe,” a use unique to it that 「または／もしくは」 lack. 「あるいは」 has two uses: ① as “or” (joining two options, = または): here it goes in the middle of “A あるいは B” for “A or B”: 徒歩あるいは自転車で行く (go on foot or by bicycle), 賛成あるいは反対、どちらかを選ぶ (for or against, choose one). This use is like 「または,」 just that 「あるいは」 is more refined, written. ② expressing the conjecture “perhaps, maybe” (an adverb, at the sentence head): here it stands alone at the sentence head, often with 「かもしれない・だろう,」 for the conjecture “perhaps, maybe”: あるいは、彼はもう知っているのかもしれない (perhaps he already knows), あるいは成功するかもしれないが、油断は禁物だ (perhaps it'll succeed, but don't let your guard down), 雨が降るか、あるいは雪になるかもしれない (it might rain, or perhaps turn to snow). This “perhaps” conjecture use is unique to 「あるいは」 — 「または」「もしくは」 can only be “or,” not “perhaps.” So distinguish: 「あるいは」 between two options (A あるいは B) → “or”; 「あるいは」 at the sentence head, followed by かもしれない → “perhaps, maybe” (conjecture). Test trick: look at 「あるいは」's position and what follows — sandwiched between two parallel options → “or”; at the sentence head with a conjectural tone (かもしれない) → “perhaps.” This is a use 「あるいは」 has beyond 「または／もしくは,」 often tested at N1 — remember “あるいは = or ＋ perhaps” and you won't miss it.

🖊️ Practice Questions (5)

Q1. 「鉛筆___ボールペンで書いてください。」(pencil or ballpoint pen)

(A) または　(B) それとも　(C) しかも　(D) ところが

Q2. What is the register of 「もしくは」?

(A) formal, written (common in regulations/official documents)

(B) children's speech

(C) internet slang

(D) command form

Q3. Which corresponds to the 「or」 in a question sentence?

(A) それとも

(B) もしくは

(C) または

(D) あるいは

Q4. What does 「電話もしくはメール」 mean?

(A) phone or email (pick one of the two)

(B) both phone and email are required

(C) neither phone nor email

(D) phone only

Q5. Which usage is natural?

(A) 現金または振込でお願いします。　(B) コーヒーもしくはお茶?(疑問は それとも)

(C) または食べる(単独)。　(D) もしくはだ高い。

Answer Explanations

1. (A) または ── Pencil or ballpoint pen.

2. (A) ── Formal, written.

3. (A) それとも ── The 「or」 in a question.

4. (A) ── Phone or email (pick one of the two).

5. (A) ── 「現金または振込」 is correct.