Differences between "ga" and "wa"


Let's study about this big theme step by step.

Rule1: A particle, "ga" never comes after "when, where, who, what"
                                                                    = itsu, doko, dare, nani

Dare ga ikimasu ka?                                                               ( Who will go?)
       Watashi ga ikimasu.                                                                ( I will go).

        Itsu ga ichiban tsugoo ga iidesu ka?                                         (When's most convenient for you?)
        Konban 7ji ga iidesu.                                                              (7 p.m tonight would be the best). 
        8ji wa doo desuka?                                                                ( How about 8.pm ? )

        Nani ga tabetai desu ka?                                                        (What would you like to  eat?
        Sashimi ga tabetai desu.                                                        (I want to eat sashimi).


       * You can use other particles after question words listed above, for example,
         "Dare ga, dare ni, dare to, dare kara"  means "who, to whom, with whom, from whom".
          The particle shows gramatical relationship between a word and word in a sentence.
          Strictly speaking, there are some categories in particles, but it is a first step to memorize some typical particles
          such as "ga, no, ni, o, e (へ), to, kara, de, ya"
       * You can lead a definition, "ga" is used for an answer for these types of questions.
          In other words, you can assume an interrogative sentence preceding this sentence.

       * You can see how each particle is used in a sentence/paragraph through "Romaji Nihongo Happy-go-lucky"

Rule 2: "wa" is used for a topic, and "ga" is used for a focus.
            In other words, "ga" is used for new information.
and "wa" is used for old information.

           Yuki wa watashi no omoi kokoro ni furu.                                      (Snow falls on my depressed heart).
            old information                            old information
                       watashi no omoi kokoro ni
                        new information

            Onaka ga itai desu.                                                                  (I have a stomahache).
             is focused
             is a small subject

            * The full sentence is "Watashi wa onaka ga itai desu".
                                             is a topic
                                             is a big subject

Rule 3: "wa" is used for contrast

             Watashi wa ikimasu ga, kanai wa ikimasen.                                 (I will go, but my wife will not go).
             Sushi wa suki desu ga, unagi wa kirai desu.                                (I like sushi, but I do not like eel).

Rule 4: "explanation → topic" #1
"topic → explanation" #2

           #1 Watashi ga Suzuki desu.                                              (I am Suzuki).i←Which person (who) is Suzuki?
           #2 Suzuki wa watashi desu.                                               (Suzuki is me). ←Which person (who) is Suzuki?

           #3  Watashi wa Suzuki desu.                                              (I am Suzuki).

           * Backing to rule 2, you can recognize that the sentence #3 means that
              "As for me, I am Suzuki" or "I am going to explain about me. I am Suzuki".

           * The sentence #2 is not common.

          Sore o tabeta no wa watashi desu.                                              (I am the one who ate it).

          *Can you suppose a sentence preceding this sentence in above?

            Please send us your ansewr, question and any kind of feedback.