Verb Groups

To conjugate Japanese verbs correctly, you must first identify their group:

1. Group 1（五段 - ごだん）:
These are 'consonant-stem' verbs. The name 'godan' literally means 'five rows', referring to how the final vowel shifts through the five rows (a, i, u, e, o) of the hiragana chart during conjugation. A key rule is that any verb that does not end in 〜る is automatically a Group 1 verb (e.g., 買う（かう）, 行く（いく）, 飲む（のむ）). If a verb does end in 〜る, it is still Group 1 if the vowel before it is an a, u, or o sound (like 分かる（わかる））—with the exception of the irregular verbs する and 来る（くる）. For example, the final う sound changes to an い sound before adding the polite ます form ending (e.g., 飲む（のむ） becomes 飲みます（のみます）). Note that 行く（いく） is a Group 1 verb, though it has a unique て form: it becomes 行って（いって） instead of the expected 行いて（いいて）. Another major exception is ある (to be/exist), which is a Group 1 verb but has a completely irregular negative form (ない form instead of あらない). Additionally, there are five 'Special Godan' honorific verbs: いらっしゃる, なさる, くださる, おっしゃる, and ござる. These are irregular because their polite forms end in 〜います instead of 〜ります (e.g., いらっしゃいます). Four of these (いらっしゃる, なさる, くださる, おっしゃる) also have imperative forms ending in 〜い instead of 〜れ (e.g., ください instead of くだされ), while ござる has the imperative ござれ (though this is highly archaic and rarely used in modern Japanese outside of period dramas or fixed expressions). Finally, the verbs 問う（とう） and 乞う/請う（こう - to beg/request） are Group 1 verbs that do not end in 〜る, but have irregular て forms and た forms (問うて（とうて）/問うた（とうた） and 乞うて/請うて（こうて）/乞うた/請うた（こうた） instead of 問って（とって）/問った（とった） and 乞って/請って（こって）/乞った/請った（こった）).

2. Group 2（一段 - いちだん）:
These are 'vowel-stem' verbs. The name 'ichidan' means 'one row', because the stem vowel remains on exactly one row of the hiragana chart during conjugation. You usually just drop the 〜る and add the new ending. They always end in 〜る, and the syllable immediately before 〜る ends in an い or え sound (e.g., 食べる（たべる）, 見る（みる）). Note that the verb くれる is a standard Group 2 verb but has a completely irregular imperative form (くれ instead of くれろ).

3. Group 3（不規則 - ふきそく）:
This group consists exclusively of two irregular verbs: する (to do) and 来る（くる - to come）. This group also includes compound verbs where a noun is combined with する (e.g., 勉強する（べんきょうする）) and compound verbs ending in 来る（くる） (e.g., 連れて来る（つれてくる - to bring someone）, 持って来る（もってくる - to bring something）).

Important Exceptions: Some verbs look exactly like Group 2 (having an い or え sound before 〜る) but actually belong to Group 1. When written in kanji, there is a helpful visual hint: if the okurigana (hiragana attached to the kanji) is two characters long (e.g., 食べる（たべる）, 決める（きめる）), it is almost certainly a Group 2 verb. However, if the okurigana is just 〜る, it could be a Group 1 exception (like 帰る（かえる - to return）, 入る（はいる - to enter）, or 走る（はしる - to run）) OR a short Group 2 verb (like 見る（みる - to see）, 寝る（ねる - to sleep）, or 着る（きる - to wear）). These single-character okurigana verbs must simply be memorized as you encounter them.