sansei-vs-doukan

Japanese has several ways to say “I agree,” but 賛成 (sansei) and 同感 (doukan) are not interchangeable. One is used when you vote yes on a proposal; the other is used when you share the same feeling about something. Getting this wrong won’t cause misunderstanding, but using them precisely is the mark of a natural speaker. This guide shows you exactly when to use each.

Yuka

Rei, my teacher mentioned 賛成 and 同感 today. What’s the difference?

Rei

Great question! Both come up a lot in everyday Japanese. The trick is knowing which context calls for which — let me show you!

At a Glance: 賛成 vs. 同感

賛成 (sansei) — Agreeing with a Proposal

賛成 is the word you use when someone puts forward a plan, idea, or suggestion and you want to say “Yes, I support that.” It is about actively endorsing something — like raising your hand in a vote. The nuance is that there was a proposal on the table and you are saying “count me in.”

Pattern: ___に賛成する (to agree with / support ___)

Example 1 — agreeing to a plan:

その計画に賛成します。
Sono keikaku ni sansei shimasu.
I agree with that plan.

Example 2 — voting yes:

賛成の人は手を挙げてください。
Sansei no hito wa te wo agete kudasai.
Those who agree, please raise your hand.

Example 3 — casual agreement:

A: 今日は早めに終わりにしましょう。 B: 賛成！
A: Kyou wa hayame ni owari ni shimashou. B: Sansei!
A: Let’s wrap up early today. B: I agree!

Yuka

I see… so context really matters with 賛成? It’s not just about the literal meaning?

Rei

Right! Japanese often works that way. 賛成 especially has nuances that go beyond a direct translation — keep that in mind.

同感 (doukan) — Sharing the Same Feeling

同感 expresses that you feel or think exactly the same as another person about something they said. It is closer to “I know exactly what you mean” or “I feel the same.” It responds to a statement about feelings, impressions, or opinions — not to a proposal or request for action.

The standard phrase is: 同感です (I feel the same way / I agree completely)

Example 1 — agreeing with an opinion:

A: この映画、ちょっと長すぎると思います。 B: 同感です。
A: Kono eiga, chotto nagasugiru to omoimasu. B: Doukan desu.
A: I think this movie is a bit too long. B: I feel the same way.

Example 2 — business context:

その点については全く同感です。
Sono ten ni tsuite wa mattaku doukan desu.
I completely agree on that point.

Example 3 — written / formal:

ご意見には同感するところが多いです。
Go-iken ni wa doukan suru tokoro ga ooi desu.
I find much that resonates with your opinion.

Yuka

Got it. And 同感 — is that the opposite, or more like a different usage?

Rei

More of a different usage! 同感 carries its own feel. Comparing them together like this is actually the fastest way to master both.

The Crucial Difference: Proposal vs. Statement

The easiest way to choose the right word is to identify what type of speech act you are responding to:

Register Note: 同感 is More Formal

賛成 is comfortable in both casual and formal settings — you can shout 賛成！ at a meeting or use it in a text message. 同感, on the other hand, sounds quite formal when used in everyday conversation among young people. In casual speech, Japanese people more often say そうだね (sou da ne) or 私もそう思う (watashi mo sou omou) instead of 同感 to express the same feeling.

Decision Flowchart

Someone said something. Do you agree?
        |
Was it a PROPOSAL or SUGGESTION?
(e.g., "Let's do X", "How about X?")
        |
   YES                   NO — it was an OPINION or FEELING
    |                     |
 賛成 (sansei)       同感 (doukan)
"I agree / I support it"   "I feel the same way"
(casual to formal)         (more formal/written)

Quick Quiz

Yuka

I think I’ve finally got it! Let’s take the quiz to be sure.

Rei

Perfect confidence check! Let’s go — you’ve got this!

Choose the correct word — 賛成 or 同感:

1. A:「会議を短くすべきだと思います。」B:「___です。」 (賛成 / 同感)
2. A:「この計画でいきましょう。」B:「___！」 (賛成 / 同感)
3. ___の人は挙手してください。 (賛成 / 同感)
4. A:「最近、残業が多すぎますよね。」B:「___です。」 (賛成 / 同感)
5. その提案には___できません。 (賛成 / 同感)

Answers: 1. 同感　2. 賛成　3. 賛成　4. 同感　5. 賛成

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