自分で？一人で？
If I want to say I am going to Japan on my own/by myself, which is correct. Same for if I want to say I am studying (or doing anything else) on my own. And can you please explain the difference in meaning.

自分で日本へ行きます
一人で日本へ行きます

Question

自分で？一人で？
If I want to say I am going to Japan on my own/by myself, which is correct.  Same for if I want to say I am studying (or doing anything else) on my own. And can you please explain the difference in meaning.

自分で日本へ行きます
一人で日本へ行きます

Answer

自分で日本へ行きます。I'll go to Japan on my own（without asking someone to do it instead of me）.
一人で日本へ行きます。I'll go to Japan alone（because my friend suddenly became sick）.
I am studying (Japanese) on my own. 私は自分で／独力で（日本語を）勉強しています。

Answer

Really good question! I'm not japanese but I would guess it's 一人で日本に行きます。

自分で=by myself/by yourself 
一人で=on my own/ on your own

But that could very well be wrong haha

Interested to see the answer from a native speaker!