| A frequently-occurring Japanese verb base, sometimes called the "noun-forming base", as a verb in Base 2 with no other endings acts as a noun.
Godan verbs end in -i in Base 2. Ichidan verbs end in a variety of vowels, as noted below:
To put a Godan verb in Base 2, follow this pattern:
To put an Ichidan verb into Base 2, remove the ru from the verb, as follows:
There are many, many functions for Base 2. In particular, the masu form (normal-polite) requires Base 2. The masu form actually encompasses several endings:
-masu: present tense indicative
-masen: present tense negative
-mashita: past tense
-masen deshita: past tense negative
-mashoo: inclusive imperative
Some examples:
Yokuyama-san ka? Hai, koko ni imasu.
Mr. Yokuyama? Yes, he is here.
Iie, kaerimasen.
No, I'm not going home.
Kyoo wa ane no uchi ni asa-gohan o tabemashita.
Today I ate breakfast at my sister's house.
Ani no uchi ni tabemasen deshita.
I didn't eat at my brother's house.
Ikimashoo, ne?
Let's go, eh?
Another common use of this base is to combine it with mono (thing) to make a noun that refers to the action of the verb. For example, tabemono means "thing(s) to eat" and kaimono means "things to buy", i.e. shopping.
Kaimono o shimasu ka.
Are you going shopping?
Base 2 is also used to form the desiderative (expressing the concept of "want"). This is done by adding -tai to Base 2. Note that this makes the verb into an adjective, and as such it may be inflected to show past, negative, etc, like all other Japanese adjectives. Examples:
Kaeritai desu.
I want to go home.
Kaeritakatta desu.
I wanted to go home.
Sore wa tabetakunakatta desu.
I didn't want to eat that.
Myriad other endings are possible, including -dasu (to suddenly start doing, do suddenly), -kata (how to, way of doing), -owaru (finish doing), and so forth. Keep in mind that many of the Base 2 endings are themselves verbs, and may need further inflection to express a complete thought at the appropriate level of politeness. | 
