How to form past and present for ru-verbs and u-verbs
To form the past and present tenses for ru-verbs and u-verbs in Japanese, here’s a clear summary:
Overview: Key takeaway
Ru-verbs (Ichidan verbs) have a straightforward conjugation pattern where the final る is dropped before adding tense endings. U-verbs (Godan verbs) involve changing the final syllable’s vowel sound before attaching endings, resulting in more varied past tense forms. This distinction is critical for accurate and natural Japanese speaking.
Ru-verbs (Ichidan verbs)
- Present (dictionary/plain form): The verb ends in る (ru), e.g., 食べる (taberu) “to eat”.
- Present polite form: Drop the る and add ます, e.g., 食べます (tabemasu).
- Past (plain form): Drop the る and add た, e.g., 食べた (tabeta).
- Past polite form: Drop the る and add ました, e.g., 食べました (tabemashita).
Ru-verbs are often called Ichidan (“one-step”) verbs because conjugating them involves just removing the final る and adding the relevant ending. This simplicity makes ru-verbs particularly friendly for beginners. Most ru-verbs end with える (eru) or いる (iru), such as 起きる (okiru) “to wake up” or 見る (miru) “to see”.
Pronunciation note
When adding ます or ました, the pronunciation remains close to the base verb stem. For 食べます, the stem 食べ (tabe) is pronounced with a short, clear “e” vowel sound, making the polite forms easy to pronounce and recognize in conversation.
U-verbs (Godan verbs)
- Present (dictionary/plain form): The verb ends in a u vowel sound (except ru verbs that are ru-verbs), e.g., 読む (yomu) “to read”.
- Present polite form: Change the final u-vowel sound to its corresponding i-vowel sound and add ます, e.g., 読みます (yomimasu).
- Past (plain form): The past tense varies depending on the final syllable but often ends in った, んだ, いた, or った, e.g., 読んだ (yonda).
- Past polite form: Change the final u-vowel sound to i-vowel and add ました, e.g., 読みました (yomimashita).
U-verbs, or Godan (“five-step”) verbs, are named after the five different vowel bases their terminal syllable can shift among during conjugation. The main challenge for learners is the varying past tense endings which depend on which consonant preceded the u vowel.
Common patterns for u-verbs’ past plain form:
- Verbs ending with う (u), つ (tsu), and る (ru) → replace with った (tta)
- E.g. 会う (au) → 会った (atta), 待つ (matsu) → 待った (matta)
- Verbs ending with む (mu), ぶ (bu), ぬ (nu) → replace with んだ (nda)
- E.g. 飲む (nomu) → 飲んだ (nonda), 遊ぶ (asobu) → 遊んだ (asonda)
- Verbs ending with く (ku) → replace with いた (ita) (except 行く “iku,” which uses った (itta))
- E.g. 書く (kaku) → 書いた (kaita), but 行く (iku) → 行った (itta)
- Verbs ending with ぐ (gu) → replace with いだ (ida)
- E.g. 泳ぐ (oyogu) → 泳いだ (oyoida)
- Verbs ending with す (su) → replace with した (shita)
- E.g. 話す (hanasu) → 話した (hanashita)
Why this matters
These sound changes were inherited from classical Japanese phonology and are essential to sounding natural. For example, incorrectly forming 話した (hanashita) as *話すた would sound odd to native speakers. This explains why u-verbs require memorizing these conjugation patterns, especially their past tense forms.
Conversation tip
In natural speech, the plain past form of u-verbs is one of the most commonly heard forms—for example, 読んだ (yonda) for “read (past).” Active listening and practice help internalize these patterns far better than rote memorization.
Comparison between ru-verbs and u-verbs
| Aspect | Ru-verbs (Ichidan) | U-verbs (Godan) |
|---|---|---|
| Final ending in dictionary form | Always る (る) | Ends in u-vowel sound, various consonants |
| Present polite formation | Drop る + ます (食べる→食べます) | Change final u → i + ます (読む→読みます) |
| Past plain formation | Drop る + た (食べる→食べた) | Change stem and add た variants (読む→読んだ) |
| Past polite formation | Drop る + ました (食べました) | Change stem + ました (読みました) |
| Learning difficulty | Easier due to regular pattern | Harder due to multiple sound changes |
Understanding this difference prevents common errors, such as failing to shift the vowel in u-verbs or wrongly treating u-verbs as Ichidan, which leads to unnatural conjugations.
Common mistakes and pitfalls
- Confusing ru-verbs with u-verbs ending in る: Not all verbs ending with る are ru-verbs; many are u-verbs. For example, 取る (toru) “to take” is an u-verb, conjugates like 取った (totta), not 取た.
- Incorrect past formation of u-verbs: Applying the ru-verb past pattern (drop る + た) to u-verbs leads to ungrammatical forms, e.g., *読た instead of 読んだ.
- Overgeneralizing polite form patterns: The polite present for u-verbs requires changing the ending vowel to i before adding ます; skipping this step results in incorrect forms.
Step-by-step guide to conjugate u-verbs into past plain form
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Identify the verb’s dictionary form ending syllable (e.g., う, く, ぐ, す, etc.).
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Consult the conjugation rule for that syllable:
Ending Past plain ending Example Past form う, つ, る った 待つ (matsu) 待った (matta) む, ぶ, ぬ んだ 飲む (nomu) 飲んだ (nonda) く いた 書く (kaku) 書いた (kaita) ぐ いだ 泳ぐ (oyogu) 泳いだ (oyoida) す した 話す (hanasu) 話した (hanashita) -
Apply the sound change to the verb stem.
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Use the past form in conversation or writing.
FAQ: Clarifying common questions
Q: How do I know if a る-verb is ru-verb or u-verb?
A: Generally, if the verb stem ends with え or い before る, it is likely an ru-verb (e.g., 食べる, 見る). If it ends with other vowels, it may be an u-verb (e.g., 取る (to take)).
Q: Why does 行く (iku, “to go”) conjugate differently in past?
A: 行く is an exception among く-ending u-verbs; its past form is 行った (itta), not 行いた. This exception is common enough to be frequently learned early.
Q: Is the past polite form conjugated the same way for ru-verbs and u-verbs?
A: Both conjugate by changing the final syllable to the i-form and adding ました, but ru-verbs simply drop the る first, while u-verbs shift vowels and add ました (e.g., 食べました, 読みました).
This detailed understanding of ru- and u-verb conjugation supports accurate speaking and listening comprehension in everyday Japanese. Contextual conversation practice—especially hearing and using these forms actively—helps solidify these patterns faster than passive study alone.