"I went to South Korea on the weekend."
If you put the 'HA' after Korea and make it the subject, it would mean "Korea went" If you remove 'weekend' for a moment, they you can assume the phrase to be "watashi ha kankoku ni ikimashita", so naturally the subject would be 'watashi' The particle 'NI' can be used for different purposes, including places specially with some verbs like 'norimasu' > "BASU ni norimasu" = 'i ride the bus'
I agree with you gamjawoo_. I feel like the English sentence could be answering many questions:
1) Who went to South Korea this weekend?
2) Where did you go this weekend?
3) When did you go to South Korea?
My understanding is that the answer to the question goes after the は, and everything that's just the context that's assumed by the question should go before the は. So the corresponding Japanese sentences would be:
1) Who went to South Korea this weekend? 週末韓国には行きました。
2) Where did you go this weekend? 週末は韓国へ行きました。
3) When did you go to South Korea? 韓国には週末行きました。
I probably got the use of へ・に wrong but that's my understanding of how the topic marker works.
You're right confused!
There's no "subject" here. A subject is an agent that does an action, and the object has that action done to them. So, I (the subject) go (the verb/action) to South Korea (the object). In Japanese a subject is marked with が, but there's no agent mentioned here, only implied. So there's no が and no subject.
Instead the TOPIC is marked with は. In this case the topic is the weekend. The topic is basically the main point of the sentence, like sort of the reason why the sentence is being spoken. In this case, the important point is that this takes place at the weekend - so the weekend is marked as the topic.
I hope that makes sense.
I got caught out on two counts here:
Because the term for "South Korea" has previously been used to refer to "Korean" things in general, I was looking for the word "South" to add in, which isn't needed;
I keep forgetting that when referring to the weekend, you need a particle. As I recall you don't need this for words such as 昨日 (yesterday) or 今朝 (this morning). How come?