Japanese Verbal Bases - How they are formed and How to use them

Author Anna Baffa Volpe for article 'Japanese Verbal Bases - How they are formed and How to use them'

Anna Baffa Volpe

8 min reading time

After an introduction to Hiragana, Kanji, and Particles in Japanese, we are now going to explore an introduction to Japanese Grammar, its characteristics and its conjugations.

In this article, we are going to learn the 5 verbal bases at the core of the Japanese Grammar system. We are going to see how these 5 bases are formed and how they are used in the Japanese language.


Japanese verb conjugations - Ichidan and Godan verbs

The first step to conjugate verbs in Japanese is to recognize their category. In Japanese all verbs are part of 3 categories:

  • Single base verbs or Ichidan (ending in eru and iru)
  • 5-base verbs or Godan (all other cases)
  • Irregular verbs: する (do) and () (come)

The bases have various names that change according to the method used or the grammar. Nonetheless, their use in conjugations is always the same.

We are now going to learn how to conjugate the verbal bases in Japanese. We will also understand when to use each of these bases.

It is important to know the grammar rules of each base. In fact, each base corresponds to a series of very precise modes and times.

Verbal basis B1 or Negative basis

The Verbal base B1 (also called negative base) ends with the kana in “a” in the syllabic series: ka ki ku ke ko (, き, く, け, こ).

It is used to form the negative of the dictionary form of the verb, in the present and past tense.

Base[B1]+ない
Base[B1]+なかった

Verb base B1 for Ichidan verbs

Let's see some examples of how the base B1 is formed with Ichidan verbs.

食べる

The verb eat in Japanese is ()べる.

This verb becomes ()ない: I don't eat, we don't eat.

()べる
()
()ない

B1 verb base for Godan verbs

Let's see some examples of how the base B1 is formed with Godan verbs.

書く

The verb write in Japanese is ()く.

This verb becomes ()ない: I don't write, we don't write.

()
()
()
()ない

For Ichidan verbs there is no risk of making a mistake, since the conjugation only requires to remove the last る.

For Godan and Irregular verbs instead we need to know which basis is needed to form the correct conjugation.

For example, it is wrong to say (書|か)ない (kakinai), because the grammar rule for the negative conugation (B1) requires the kana in "a" (か), and not き(which instead is used in the B2 base).

(ほん)
()まなかった。

I haven't read the book.

()かなかった。

I didn't go.

Verb base B1 for irregular verbs

For irregular verbs (する and (来|く)る) the conjugation is more simple:

する
しない
()
()ない

Verb base B2 or Base in "masu" (ます)

The Verb base B2 ends with the kana in “i” in the syllabic series ka ki ku ke ko (か, , く, け, こ).

The name is already indicative of what will be formed: the polite form in masu (ます).

Base[B2]+ます
Base[B2]+ました
Base[B2]+ません
Based[B2]+ませんでした

B2 verb base for Ichidan verbs

Let's see some examples of how the base B2 is formed with Ichidan verbs.

決める

The verb decide in Japanese is ()める.

In its base B2 (polite form) the verb becomes:

  • ()ます (kimemasu) in the polite form in the present tense: I decide, we decide
  • ()ました (kimemashita) in the polite form in the past tense: I have decided, you have decided
()める
()
()ます
()める
()
()ました

B2 verb base for Godan verbs

Let's see some examples of how the base B2 is formed with Godan verbs.

書く

We have seen in the example of the base B1 the verb write ()く.

This verb becomes:

  • ()ません (kakimasen) in the polite form in the negative present tense: I don't write, we don't write
  • ()ませんでした (kakimasen deshita) in the polite form in the negative past tense: I have not written, we have not written
()
()
()
()ません
()
()
()
()ませんでした

B2 verb base for irregular verbs

As for irregular verbs:

する
します
()
()ます

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Verb base B3 or Dictionary form

The verb base B3 ends with the kana in “u” in the syllabic series ka ki ku ke ko (か, き, , け, こ).

This form is used without conjugations (plain or dictionary form) in the affirmative plain form.

The B3 verb conjugation therefore remains as it is in its original form (Dictionary form) without adding any suffix
(しょう)(せつ)
()む。

I'm reading a novel.

(ちゃ)
()む。

I have tea.

The base B3 is also used in the form of the verb to be able to do something, to know how to do something, using ことができる.

Base[B3]+こと++できる
日本語(にほんご)
(はな)すことができる。

I can speak Japanese.

Note that this form is often shortened by omitting the verb: 日本語が出来る = I can speak Japanese.

Verbal basis B4 or Hypothetical basis

The verb base B4 ends with the kana in “e” in the syllabic series ka ki ku ke ko (か, き, く, , こ).

Using this form we can express conditional or hypothetical actions or states: if you do something ....

Base[B4]+れば
Base[B4]+
れば (reba) is used for Ichidan verbs, while ば (ba) alone is used for Godan verbs
メガネ
かければ、
よく
()えます。

If you put on your glasses you can see clearly.

(まい)(にち)
8()(かん)
(べん)(きょう)すれば、
(じょう)()
になります。

If you study 8 hours a day you will improve.

Irregular verbs

As for irregular verbs:

する
すれば
()
()れば

Verbal basis B5 or Imperative basis

The verb base B5 ends with the kana in “o” in the syllabic series ka ki ku ke ko (か, き, く, け, ).

Using the basis B5 we form the imperative, which expresses orders or commands and is often accompanied by the exclamation point.

For single base verbs (Ichidan) add the suffix ろ (ro) or よ (yo) to the stem.
For 5-base verbs (Godan) imperative form we instead use the base B4 without adding suffixes.

B5 verb base for Ichidan verbs

  • 食べろ!- Eat! (Tabero!)
  • 起きろ!- Wake up! (Okiro!)
  • 決めろ!- Make up your mind! (Kimero!)
()べる
()
()
()きろ
()
()
()める
()
()

B5 verb base for Godan verbs

  • 書け!- Write! (Kake!)
  • 早く飲め!- Hurry up and drink! (Hayaku name!)
()
()
()
(はや)()
(はや)()
(はや)()

You now know all the 5 basis which are at the core of the Japanese Grammar system.

These bases are sometimes used individually, while other times combined with the various suffixes that we have seen determine modes, times, and all the other forms of the verb.

It is important to learn and remember all these forms in order to be able to move to more advanced grammar rules of the language.

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