The conditional form – verbs

The conditional form of Japanese of verbs is constructed differently depending on whether the verb is a -ru, -u or irregular verb

-ru verbs

For -ru verbs, the stem remains unchanged. For example, to make the imperative form of 食べる for example, use the same stem as in the other forms, followed by the verb ending れば.

食べ・る → 食べ・れば

-u verbs

With -u verbs, a new stem is made by changing the vowel sound of the last hiragana of the plain form from an う character to the corresponding え character. This results in the same stem that we learned to use for the imperative form. Then add the verb ending ば.

書く → 書け・ば

Irregular verbs

The conditional form of する is すれば.
The imperative form of 来る is 来れば(くれば).
行くfollows the same rule as for -u verbs, with an imperative form 行けば.

In romaji

In romaji, it is even simpler. for all verbs, simply swap the -u ending of the plain form for -eba.

Miru → mireba
Oyogu  → oyogeba
suru  →  sureba
kuru  →  kureba
iku  →  ikeba