Irregular Verbs


Japanese irregular verbs, notably 「する」(to do) and 「くる」(to come), stand out due to their unique conjugation patterns that diverge from the regular rules applied to る-verbs and う-verbs.

Mastery of these irregular verbs is essential for navigating daily conversations, formal communications, and various grammatical constructions in Japanese.

The Core Irregular Verbs

「する」(to do)

As one of the most versatile verbs, 「する」is used to create actions from nouns and stands out due to its distinct conjugation forms, such as します (shimasu) for the polite present and しない (shinai) for the negative.

「くる」(to come)

Equally pivotal, 「くる」describes movements towards the speaker or a specified place.

It features unique conjugations like きます (kimasu) for the polite present and こない (konai) for the negative.

Below is a comprehensive table showcasing how the irregular verbs 「する」 (to do) and 「くる」 (to come) conjugate in various forms:

Other irregular verbs

「行く」(to go)

Often considered a regular う-verb, 「行く」has unique te-form and past tense conjugations, transforming into 「行って」(itte) and 「行った」(itta), respectively.

This deviation from standard う-verb conjugation warrants special attention.

Special Expressions

Verbal expressions with the auxiliary verb “たい” or “ない” may also have irregular conjugations in certain contexts.

For example, “I want to eat” (tabe-tai) and “I don’t want to eat” (tabe-nai) are considered to deviate slightly from the rules as verbs because of their adjectival nature.

Strategies for Mastery

  • Regular Practice: Engaging with the language through speaking, writing, and listening exercises helps solidify the irregular patterns in your memory.

  • Contextual Learning: Exposure to natural Japanese through media, literature, and conversation aids in understanding the application of irregular verbs in real-life scenarios.

  • Grammar Resources: Utilizing textbooks, online courses, and language apps can provide structured learning paths and clarify the intricacies of irregular verbs.


Irregular verbs in Japanese, particularly 「する」 and 「くる」, play a crucial role in the language’s grammar and expressiveness.

Expanding your study to include all irregular verbs and their unique conjugations enhances your ability to communicate complex ideas and navigate various linguistic contexts.

Through dedicated practice and immersion, mastering these irregularities becomes a rewarding milestone in the journey to fluency in Japanese.