I know it's a complicated grammar concept that even Japanese don't fully get, but I'd like to know what's the difference between

明日は火曜日です and 明日が火曜日です

They way I understand it, in the second sentence you're indicating that tomorrow, and not any other day, is Tuesday. And in the first one, you're indicating that tomorrow is Tuesday, and not any other day.

Would this be correct?

2 Answers 2


The former (明日は…) is an answer to a question "What day is tomorrow?" while the latter (明日が…) is that to "When is Tuesday?".

Edit: "Topic" stands for imformation that's suggested in the preceding context, so when we see 明日は…, we can imagine some contexts that include "明日" e.g. "明日は何曜日?". On the other hand, 明日が火曜日 is inversion of 火曜日は明日, and we can think of one that includes 火曜日 e.g. "火曜日はいつ?".

  • 2
    And how would you ask in Japanese, いつが火曜日ですか or ...?
    – Tim
    Jul 25, 2014 at 16:44
  • That's fine but 火曜日はいつ(ですか) is more common. 明日が火曜日 is inversion of 火曜日は明日.
    – user4092
    Jul 26, 2014 at 3:18
  • 2
    I was not sure before but I think the response to 火曜日はいつ(ですか) would be 火曜日は明日ですor more likely, just 明日 (or perhaps even more likely, 月曜日の次の日(?)). I struggle to think of a situation where anyone would say 明日が火曜日です but it is the answer to いつが火曜日ですか. Both are grammatical but not very natural.
    – Tim
    Jul 26, 2014 at 3:43

明日が... Siginifies specificity and maybe importance (I think), e.g., 明日が会議 or 明日が試合。明日は seems to imply something more vague or mundane, e.g. 明日は仕事 or 明日は暇。You wouldn't say 明日が暇だ。

So, 明日は火曜日 is "tomorrow is (just a) Tuesday," whereas 明日が火曜日 might be more like, "Dude, tomorrow is THE Tuesday, when something special is happening." And when you turn it in to a question, 明日が火曜日?may imply, "Tomorrow is Tuesday? The day I have to do a lot of important crap?"

  • I don't know why this has gotten two down votes. What @user6888 is saying is not wrong. Jul 28, 2014 at 13:21

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