Translation guide
In Japanese, 'regular conjugation' refers to predictable verb and adjective inflection patterns. The two main regular verb types are godan (u-verbs) and ichidan (ru-verbs). Adjectives also follow regular patterns. This guide helps learners understand and apply these rules.
The learner wants to understand the two main regular verb conjugation types in Japanese.
Godan verbs (also called u-verbs) are one of the two regular verb types. They have stems ending in a consonant, and the final kana changes across the five vowel rows (a, i, u, e, o) to attach different endings.
「書く」は五段活用の動詞です。
"Kaku" (to write) is a godan verb.
Ichidan verbs (also called ru-verbs) are the other regular type. They always end in -iru or -eru in the dictionary form, and the stem remains unchanged when conjugating; endings are simply added.
「食べる」は一段活用の動詞です。
"Taberu" (to eat) is an ichidan verb.
Most verbs ending in -iru or -eru are ichidan, but some are godan (e.g., 帰る, 切る). Verbs not ending in -iru/-eru are always godan. When in doubt, check a dictionary.
「起きる」は一段、「走る」は五段です。
"Okiru" (to get up) is ichidan, "hashiru" (to run) is godan.
Godan verbs have six base forms (未然, 連用, 終止, 連体, 仮定, 命令) used to build various conjugations. The stem-final consonant shifts across the kana rows.
「読む」の未然形は「読ま」、連用形は「読み」です。
The mizenkei of "yomu" is "yoma", and the renyōkei is "yomi".
The learner wants to know how i-adjectives and na-adjectives conjugate regularly.
I-adjectives end in -i and conjugate by changing the final -i to -ku, -katta, -kereba, etc. Na-adjectives use the copula (da/desu) for conjugation, with the adjective stem unchanged.
「高い」は「高くない」「高かった」のように活用します。
"Takai" (expensive) conjugates as "takakunai" (not expensive), "takakatta" (was expensive).
Na-adjectives do not conjugate themselves; instead, they are followed by forms of the copula (だ/です) which conjugate. For example, 静かだ (is quiet), 静かではない (is not quiet), 静かだった (was quiet).
「静か」は「静かではない」「静かだった」のように使います。
"Shizuka" (quiet) is used as "shizuka dewa nai" (not quiet), "shizuka datta" (was quiet).
The learner wants to understand how 'da/desu' conjugates regularly.
The copula 'da' (plain) and 'desu' (polite) follow regular conjugation patterns. Plain: da, dewa nai, datta, dewa nakatta. Polite: desu, dewa arimasen, deshita, dewa arimasen deshita.
「学生だ」の過去形は「学生だった」です。
The past form of "gakusei da" (is a student) is "gakusei datta" (was a student).
While most verbs are regular, two very common verbs are irregular: する (suru, to do) and 来る (kuru, to come). Their conjugations must be memorized separately.
する → しない、した、して
suru → shinai (not do), shita (did), shite (te-form)
Mastering regular conjugation is essential for forming tenses, negatives, conditionals, and connecting clauses. Practice by conjugating a few godan and ichidan verbs daily until the patterns become automatic.