Use particle wa or ga in Japanese

The subtle distinction between Japanese particles は (wa) and が (ga) makes it difficult to choose between them. Here I will show you a simple way to get it right every time.

Professor Eleanor Jorden of Cornell University taught me that we actually have the same thing in spoken English. We stress words in a sentence to emphasize them. Consider:

"THIS is delicious"emphasizes that this one is the delicious one, as compared to others. In this situation you use が (ga);

これがおいしい。    (Kore ga oishii.)

Be careful to offer kind words about the others so that nobody feels left out:

それも食べたいですね。    (Sore mo tabetai desu ne.)

"This is DELICIOUS" emphasizes the taste; the thing being tasted is already established. In this situation you use は (wa);

 これはおいしい。    (Kore wa oishii.)

Since the thing that is delicious is clear, Japanese speakers commonly drop これは and just say, 

おいしい。   (Oishii.)

As demonstrated by the above examples, が (ga) emphasizes the word to which it is attached, and は (wa) de-emphasizes the word in favor of the rest of the sentence. Another way to tell the difference is to ask yourself which word you might repeat in colloquial speech:

• これ、これがおいしい！  (This one, this is delicious!) uses ga.
• これはおいしい！うまい！  (This is delicious! Tasty!) uses wa.

Interrogatives

Interrogatives like "which?", "what?" and "who?" can be followed by all kinds of particles and words, including が (ga), but never は (wa):

どれがおいしいか。   (Dore ga oishii ka.)

だれは…                      (Dare wa...) [Incorrect]

Returning to how we stress words in spoken English, one might say "WHICH is delicious?" In Japanese this calls for が (ga). We would never say, "Which is DELICIOUS?", which corresponds to the incorrect は (wa).