「Verb + たら」always have ambiguous meanings?

Question

I agree that ～たら is one practical tool that could express lots of meanings. but sometimes it became one problem for students of japanese.

If I say:

• 日本に行ったら、友達を訪ねます。

it's : If I go to Japan, I will visit my friend.(?)
or: When I get to Japan, I will visit my friend.(?)

• 卒業したら、旅行したいと思います。

it's : If I graduate (it's a possibility), I want to travel.
or: After graduating (it's certain), I'm think of traveling.

.

Does the meaning depend on the context? or Is there a better way to say that sentences?

Answer 1

These examples sound more like "when" to me. If you wanted to emphasize an "if", you could add もし to the beginning.

• もし日本に行ったら、．．．
• もし卒業したら、．．．

However, "when" may also carry a bit of uncertainty to it, so it's a little ambiguous. "When I go to Japan..." You might be certain that you're going and it's just in the future at this point, or you may be speculating, as in "If I ever go."

You could also use a different construct to force this. Refer to this important post for more options and their rules.