This page will give you a complete overview of all the conjugations in the Japanese language, including all irregular verbs. For detailed information on how each conjugation is used click the appropriate links.

In modern Japanese there are two types of words which are conjugated:

Verbs have five conjugations in modern Japanese and verbal adjectives have four:

Verbs
Verbs are divided into two groups, known as group 2 verbs, or nidan katsuyou (二段活用) and group 4 verbs, or yodan katsuyou (四段活用). Each group has its own conjugations. There are two irregular verbs, and a group of five honorific verbs that have two irregular conjugations.

Verbs belong to group 2* when the rentaikei conjugation ends on "-eru" or "-iru".

Group 2 conjugations		to eat		to see
Rentaikei 連体形		食べる taberu		見る miru
Ren'youkei 連用形		食べ tabe		見 mi
Izenkei 已然形		食べれ tabere		見れ mire
Mizenkei 未然形		食べ tabe		見 mi
Meireikei 命令形		食べよ/ろ tabe yo/ro		見よ/ろ mi yo/ro

NOTE: There are verbs belonging to group 4 where the rentaikei conjugation ends on "-iru" or "-eru", these verbs are indicated in the vocabulary list with the ④ mark.

All other verbs belong to group 4.

Group 4 conjugations		to write		to buy		to wait		to lend
Rentaikei 連体形		書く kaku		買う kau		待つ matsu		貸す kasu
Ren'youkei 連用形		書き kaki		買い kai		待ち machi		貸し kashi
Izenkei 已然形		書け kake		買え kae		待て mate		貸せ kase
Mizenkei 未然形		書か kaka		買わ kawa		待た mata		貸さ kasa
Meireikei 命令形		書け kake		買え kae		待て mate		貸せ kase

NOTE: Pay special attention to the mizenkei of verbs ending on the hiragana う (u), this conjugation uses the hiragana わ (wa) instead of あ (a).

Irregular verbs
There are two truly irregular verbs.

Irregular verbs		to do		to come
Rentaikei 連体形		する suru		来る kuru
Ren'youkei 連用形		し shi		来 ki
Izenkei 已然形		すれ sure		来れ kure
Mizenkei 未然形		し､せ､さ shi, se, sa		来 ko
Meireikei 命令形		しよ/ろ､せよ/ろ､せい shi yo/ro, se yo/ro, sei		来い koi

NOTE: There are various conjugations for the mizenkei for the verb する (suru). し (shi) is reserved for the negative form, せ (se) and さ (sa) are reserved for the causative form and the passive form.
Pay special attention to the ren'youkei and the mizenkei conjugations of 来る (kuru). Though they are written the same way, their pronunciations are different.

These honorific verbs have irregular ren'youkei and meireikei conjugations. All five verbs have the same irregularity.

Irregular conjugations		to speak		to give		to do
Rentaikei 連体形		仰る ossharu		下さる kudasaru		為さる nasaru
Ren'youkei 連用形		仰い osshai		下さい kudasai		為さい nasai
Izenkei 已然形		仰れ osshare		下され kudasare		為され nasare
Mizenkei 未然形		仰ら osshara		下さら kudasara		為さら nasara
Meireikei 命令形		仰い osshai		下さい kudasai		為さい nasai

Irregular conjugations		there is/are / to come / to go (living beings)		there is/are (objects)
Rentaikei 連体形		いらっしゃる irassharu		御座る gozaru
Ren'youkei 連用形		いらっしゃい irasshai		御座い gozai
Izenkei 已然形		いらっしゃれ irasshare		御座れ gozare
Mizenkei 未然形		いらっしゃら irasshara		御座ら gozara
Meireikei 命令形		いらっしゃい irasshai		御座い gozai

Verbal adjectives
Verbal adjectives have only 4 conjugations in modern Japanese. The meireikei conjugation does not exist. There is one irregular verbal adjective: いい (ii).

Verbal adjectives		to be large		to be new
Rentaikei 連体形		大きい ookii		新しい atarashii
Ren'youkei 連用形		大きく ookiku		新しく atarashiku
Izenkei 已然形		大きけれ ookikere		新しけれ atarashikere
Mizenkei 未然形		大きく ookiku		新しく atarashiku
Meireikei 命令形		-		-

Verbal adjective		to be good (irregular)
Rentaikei 連体形		いい/良い ii / yoi
Ren'youkei 連用形		よく/良く yoku
Izenkei 已然形		よけれ/良けれ yokere
Mizenkei 未然形		よく/良く yoku
Meireikei 命令形		-

* The Japanese make a further distinction between these two as the lower group 2, or shimo nidan katsuyou (下二段活用), ending on "-eru"; and the higher group 2, or kami nidan katsuyou (上二段活用), ending on "-iru", but for all practical purposes there is no difference between the two.