Particles Wa and Ga

[lucagalbu]

Hi all! I think that I can't even imagine how many questions about wa and ga you have answered, but I really need to understand just one thing:
if I say:
"isu wa koko ni arimasu"
I say "the chair is HERE" for instance as an answer to "Where is the chair?"
instead if I say:
"isu ga koko ni arimasu"
I say "THE CHAIR is here" for instance as an answer to "What is there here?"
Is this right?

[masaegu]

Yes, that is correct.

In your first sentence, the most important part is the 'koko' and not the 'isu' because the person asking the question 'Where is the chair' is asking for the chair's location. The person answering could have just replied, "Koko ni arimasu" (= It's here.)

But in the sentence "Isu ga koko ni arimasu", the subjet 'isu' is the most important element of the sentence as the question is "What is there?" It's not a desk or pc or fridge. It's a chair that is there. That is the hidden meaning of 'ga'.

[lucagalbu]

Great, maybe I'm beginning to figure it out!
Thanks