Do you remember all of your state-of-being verbs in English?  Am, is, are, was, were, be, being, been?  Well, get ready to throw all of that out the window because Japanese has no way of translating that verb directly.  Instead they simply declare something is so by using the Hiragana symbol of 「だ」 to a noun or na-adjective only.   You’ll see how this works once we get to the section on nouns and adjectives.  Not that  that will make it seem any less insane.

State that something is what it is with「だ」
Attach 「だ」 to the noun or na-adjective
（１）　魚。 – Fish.
（２）　魚だ。 – Is fish.

Looks easy right?  Ha ha.  No.  This is where it gets a little odd and seemingly pointless.   You don’t even need to use 「だ」to imply state of being.  Yeah.  that’s right.  It’s almost completely optional.  So if it’s completely optional then why the heck would you ever use it?  Well to simplify it for now, really it simply makes a statement more forceful and definitive.  For example the first “fish” example simply states that a fish exists whereas the second “is fish” example, reinforces and makes the statement more absolute.  Also, you can’t use this character and ask a question at the same time since it makes no logical or grammatical sense to do so unless it’s a question word such as 「どこだ」.

There are some cases though where the declarative 「だ」is absolutely necessary in order to explicity declare something’s state of being.  There are situations where the opposite is true as well.  So to sum up, it’s possible to declare something “is” without the declaritive  「だ」,  and there are times when you shouldn’t ever use it and times where you absolutely need to.  Believe it or not this isn’t entirely arbitrary but that will be explained later on.  Try not to think too much about it.

Conjugating for negative tense

Did you know that in Japanese you can conjugate nouns?  Were you also aware that you’re esentially remapping everything you knew about what it means to conjugate something (well, in regards to English anyways)?  Well, not so much really.  In Japanese the nouns and adjectives are being conjugated primarily because there really isn’t a state of being verb.  Translated into english though, we would subsitute in a state of being verb in order to make sense of it.  So lets get started.

First of all, the negative and past tenses are expressed via conjugation.  Esentially this conjugates a noun or an adjective for the purpose of stating that something either is not something (in the case of a negative tense) or that something was something (in the case of the past tense).  Seems fairly straightforward.  However, these tenses do not really declare anything like 「だ」 does.  It is possible to make these tenses do just that though by throwing that little character onto the end of the sentence but that will be covered a little later on.

Alright, so in order to conjugate something into the negative tense, you attach 「じゃない」 to whatever the noun or na-adjective you wish to conjugate.

Conjugation rules for the negative state-of-being
•Attach 「じゃない」 to the noun or na-adjective

（例） 友達　→　友達じゃない (is not friend)
Examples
（１）　魚じゃない。- Is not fish.
（２）　学生じゃない。- Is not student.
（３）　静かじゃない。- Is not quiet.

Conjugating for the past tense

Okay, now we come to conjugating for the past tense.  Not too different from the negative tense.  Just slap  「だった」 to the noun or na-adjective.  Same process.

Now it gets a little tricker but not by much.  Let’s say we want to conjugate into the negative-past-tense.  In this case, we don’t simply place both sets of characters  together and assume it works that way.  Instead we drop the 「い」 from the negative「じゃない」 and then we add the past 「かった」.

Conjugation rules for the past state-of-being
1.Past state-of-being: Attach 「だった」 to the noun or na-adjective
（例） 友達　→　友達だった (was friend)

2.Negative past state-of-being: Conjugate the noun or na-adjective to the negative tense first and then replace 「い」 of 「じゃない」 with 「かった」
（例） 友達　→　友達じゃない →　友達じゃなかった (was not friend)
（１）　魚だった。- Was fish.
（２）　学生じゃなかった。- Was not student.
（３）　静かじゃなかった。- Was not quiet.

Summary

Well, that covers it for the four state of being tenses (present positive,  past positive, negative present, negative past).  In the next lession we will cover what is known as a particle (not to be confused with a participle).  But first, here is a brief summary of what we’ve learned so far.
We’ve now learned how to express state-of-being in all four tenses. Next we will learn some particles, which will allow us assign roles to words. Here is a summary chart of the conjugations we learned in this section.

Japanese Language Course Verb Tense Summary

If you’re looking for any additional resources, I recommend either Rocket Japanese or Nihongo Japanese Video Course. You can check out my reviews page by either clicking here or by clicking on the Reviews tab at the top of the page.