Page 142 - Easy Japanese - Learn to Speak Japanese Quickly! (TUTTLE)

Ru-Verbs
To make the plain form of the verbs in this group, replace -masu with -ru.
In other words, you add -ru to the stem. The stem of the verbs in this group ends
in -e or -i.

Stem Meaning Informal Form

tabe eat → tabe-ru
mi look → mi-ru
Note that the -masu ending indicates that the verb is a Ru-verb but the -imasu
ending can indicate either a U-verb or a Ru-verb. You need to check the word’s

other forms to determine which group it belongs to. Also note that verbs with the
-eru or -iru ending can be either U or Ru-verbs while verbs that have other
endings are U-verbs (except for the few irregular verbs below). Iru, for example,
can be either in U-verb or Ru-verb depending on where the cut is. Examine the
following:

imasu exist → i-ru
irimasu need → ir-u

kaemasu change → kae-ru
kaerimasu go home → kaer-u

Irregular Verbs
There are only four irregular verbs in Japanese.
Formal Meaning Informal Form

form
kimasu come → kuru

shimasu do → suru
arimasu be → aru

ikimasu go → iku
The reason why arimasu and ikimasu are in this group and not U-verbs will be
explained later when we discuss the negative and past forms.

Special Polite Verbs
This group has only five verbs.
Formal form Meaning Informal Form