u-Verb Inflection

In Japan, u-verbs or Group I verbs are known as 五段活用動詞ごだんかつようどうし or 五段動詞ごだんどうし for short. Godan katsuyo (lit. "five-row conjugation") speaks directly to the inflectional tail behavior of these verbs.

Recall that the rows of the hiragana table correspond to the vowels (from top to bottom): a, i, u, e and o. 五段動詞ごだんどうし inflectional tails inflect through each of these five vowels, thus the name five-row conjugating verbs.

Basic Inflectional Tail Pattern
Form Inflectional Tail Pattern
未然形 ① ーア段
② ーオ段
連用形 ① ーイ段
② ー音便おんびん
終止形 ーウ段
連体形
仮定形 ーエ段
命令形

Table Notes:

  • "ー" represents the word stem
  • 段だん (lit. "row") refers to the row of the hiragana table – specifically refering to a corresponding to a vowel sound
  • In the hiragana table the オ段 is the bottom row, but in the case of 五段 inflectional forms, it is put in top with 未然形
  • The i-sound euphonic change (音便) is listed as a seperate inflectional tail, but it really serves the same purpose as the ーイ段 tail

Specific Inflection Examples

What are the possible endings of modern 五段 verbs in 終止形?

Godan Verb Endings
ワ ラ ヤ マ ハ ナ タ サ カ ア
(う) る ゆ む ふ ぬ つ す く う
ぶ づ ず ぐ
ぷ

In summary, no modern 五段 verbs have ず, づ, ふ, ぷ or ゆ inflectional tails.

ア行 or ワ行 Verbs?

i-Euphonic Changes (音便おんびん)

Applications

未然形

連用形

終止形

連体形

仮定形

命令形

English Names for u-Verbs

u-Verbs are also called Group I verbs in Western textbooks, but these are not the names used by the Japanese themselves.

All modern Japanese verbs end with a /u/ vowel sound, but outside the u-verbs all other verbs end with a ーる when in 終止形 and 連体形.

Some 五段 verbs do end with ーる, making them hard to distinguish from other non u-verbs in 終止形 and 連用形. The best trick remember if a ーる ending verb is a u-verb or not: ーる ending u-verbs change to ーります in masu-form, all non-u-verbs directly replace る sound with ます in masu-form.

The Group I, II and III scheme does roughly outlines the Japanese system for grouping verbs, but it is ambiguous. The Western JSL student does not really understand WHY verbs are grouped into this system due to the uninspired name.

In this section the term "u-verb" is used as a learning-bridge but it's highly recommended that you graduate to exclusively using the term 五段 verbs.