書く
かく
kaku
Conjugation
= to write
| Form | Japanese | Romaji | Meaning |
|---|---|---|---|
| Dictionary form The plain form you find in a dictionary |
書く かく |
kaku | to write |
| Masu form Polite present / future |
書きます かきます |
kakimasu | write (polite) |
| Te form Connects clauses, makes requests |
書いて かいて |
kaite | write / writing (te-form) |
| Ta form Plain past |
書いた かいた |
kaita | wrote |
| Nai form Plain negative |
書かない かかない |
kakanai | don’t write |
| Masen form Polite negative |
書きません かきません |
kakimasen | don’t write (polite) |
| Nakatta form Plain past negative |
書かなかった かかなかった |
kakanakatta | didn’t write |
| Potential form Can / be able to |
書ける かける |
kakeru | can write |
| Volitional form Let’s / I think I’ll |
書こう かこう |
kakou | let’s write |
Kaku (書く) follows the standard く-ending godan pattern without exception. Once kaku clicks, you have the template for every other regular く-verb.
Kaku is a godan (u-verb) because its dictionary form ends in く, and that く shifts across all five vowel sounds as it conjugates: か (kakanai), き (kakimasu), く (kaku itself), け (kakeru), こ (kakou). Ichidan verbs, by contrast, always end in -iru or -eru and keep a single unchanging stem — though the reverse isn’t reliable, since some common -iru/-eru verbs are secretly godan, such as 帰る (kaeru), 走る (hashiru), 知る (shiru), and 入る (hairu). Godan verbs end in う, く, ぐ, す, つ, ぬ, ぶ, む, or -る that is not preceded by an i or e sound. For the te-form and ta-form specifically, く and ぐ share their own sound change: instead of doubling a consonant, く becomes いて/いた and ぐ becomes いで/いだ, giving 書いて (kaite) and 書いた (kaita) for kaku. This differs from the doubled っ of う/つ/る verbs and the んで of む/ぶ/ぬ verbs. This いて/いた shift is the regular rule for every plain く-verb; the one common verb that breaks it is 行く (iku), which irregularly becomes 行って (itte) instead of the expected いいて (iite).
The dictionary form kaku works for plain statements about future or habitual writing and for casual speech with friends. Switch to kakimasu and kakimasen whenever the listener calls for polite register, such as talking to a teacher or in a work email. Kaite is the connector form: it links to iru for an ongoing action, to kudasai for a request, or joins onto another verb in a sequence. Kaita and kakanakatta report on finished writing, plain past positive and negative. Reach for kakeru when the point is ability or possibility rather than the act itself, and use kakou to propose writing something together or state your own intention to start.
Everyday use
昨日、日記を書いた。
Kinou, nikki o kaita.
I wrote in my diary yesterday.
Casual / Social Media
漢字で名前が書ける?
Kanji de namae ga kakeru?
Can you write your name in kanji?
Formal / Cultural context
先生への手紙を書きます。
Sensei e no tegami o kakimasu.
I will write a letter to my teacher.
Learners who first meet う/つ/る verbs like 買う and 待つ get used to a doubled consonant in the te-form (かって, まって), so they sometimes force the same pattern onto kaku and produce a wrong 書って instead of the correct kaite. A second trap is that 書く and 聞く (kiku, to listen/ask) conjugate with the identical いて/いた shift, so kaita (wrote) and kiita (heard) differ by only one mora and get misheard or mistyped for each other. Finally, the potential form kakeru is a homophone of 掛ける (kakeru, to hang) and 欠ける (kakeru, to be missing/chipped) — the kanji separates them in writing, but in spoken Japanese only context tells them apart.