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:
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).
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).
This means ru-verbs have a simpler conjugation pattern by just dropping る and adding corresponding endings, while u-verbs undergo a sound change before adding conjugation endings.
Examples:
- Ru-verb: 食べる (taberu)
- Present polite: 食べます
- Past plain: 食べた
- U-verb: 読む (yomu)
- Present polite: 読みます
- Past plain: 読んだ
This distinction is fundamental in Japanese verb conjugation. 1, 2, 7, 9, 10
Understanding the Differences More Deeply
Why Ru-verbs Are Simpler to Conjugate
Ru-verbs are sometimes called Ichidan verbs, which literally means “one step.” This refers to their straightforward conjugation: you only need to remove the last る and add the appropriate ending. This is because their stem ends with an e vowel sound, so you do not need to adjust the consonants.
For example:
- 起きる (okiru) “to wake up”:
- Present polite: 起きます (okimasu)
- Past plain: 起きた (okita)
Because the stem is stable, conjugation rules can be memorized easily, which helps beginners gain confidence quickly.
Why U-verbs Are More Complex
U-verbs (Godan verbs) involve multiple consonant and vowel changes, which is why they are sometimes called “five-step” verbs. The final syllable changes depending on the conjugation to fit Japanese phonological rules.
The key point is the last syllable’s consonant and vowel shifts to maintain natural pronunciation. For example:
-
話す (hanasu) “to speak”:
- Present polite: 話します (hanashimasu) — ‘su’ → ‘shi’
- Past plain: 話した (hanashita) — ‘su’ → ‘shi’ + た
-
泳ぐ (oyogu) “to swim”:
- Present polite: 泳ぎます (oyogimasu) — ‘gu’ → ‘gi’
- Past plain: 泳いだ (oyoida) — ‘gu’ → ‘i’ + だ
Summary Table of U-verb Past Plain Endings
| Final Syllable | Past Plain Ending Example | Example Verb | Past Plain Form |
|---|---|---|---|
| う (u) | った (tta) | 買う (kau) | 買った (katta) |
| つ (tsu) | った (tta) | 待つ (matsu) | 待った (matta) |
| る (ru)* | った (tta) | 取る (toru) | 取った (totta) |
| む (mu) | んだ (nda) | 読む (yomu) | 読んだ (yonda) |
| ぶ (bu) | んだ (nda) | 遊ぶ (asobu) | 遊んだ (asonda) |
| ぬ (nu) | んだ (nda) | 死ぬ (shinu) | 死んだ (shinda) |
| く (ku) | いた (ita) | 書く (kaku) | 書いた (kaita) |
| ぐ (gu) | いだ (ida) | 泳ぐ (oyogu) | 泳いだ (oyoida) |
| す (su) | した (shita) | 話す (hanasu) | 話した (hanashita) |
*Note: Some verbs ending in る are ru-verbs, others are u-verbs, so verification is necessary.
Common Pitfalls and How to Avoid Them
Misclassifying Ru-verbs and U-verbs
Some verbs ending with る are tricky; not all る-ending verbs are ru-verbs. For instance, 帰る (kaeru, “to return”) is a u-verb despite ending in る. Misclassification leads to wrong conjugations.
Tip: Use a dictionary or verb list to confirm. Also, ru-verbs usually have the vowel e or i sound before る, but exceptions exist.
Forgetting the Sound Changes in U-verbs
Learners often attempt to attach ます or た directly to the dictionary form without changing the last syllable. For example, mistakenly saying 読ます instead of 読みます.
Irregular Verbs and Politeness Levels
While this article covers present and past polite/plain forms, Japanese has other verb forms (te-form, negative, volitional, etc.) and irregular verbs (する, 来る). These require separate attention.
Step-by-Step Guide to Conjugating U-verbs in Present Polite Form
- Identify the verb’s dictionary form, e.g., 書く (kaku).
- Remove the final u-vowel syllable: 書く → 書
- Change the last u-vowel syllable to its corresponding i-vowel sound:
- く (ku) → き (ki)
- Add ます:
- 書 + き + ます = 書きます (kakimasu)
The same process applies for past polite (add ました instead) and other polite forms.
Step-by-Step Guide to Conjugating Ru-verbs in Past Plain Form
- Start with the dictionary form, e.g., 食べる (taberu).
- Drop the final る: 食べ
- Add た: 食べた (tabeta)
This is consistent and applies to all ru-verbs, simplifying memorization.
Quick Reference Chart: Present and Past Forms
| Verb Type | Dictionary (Plain) | Present Polite | Past Plain | Past Polite |
|---|---|---|---|---|
| Ru-verb | 食べる (taberu) | 食べます (tabemasu) | 食べた (tabeta) | 食べました (tabemashita) |
| U-verb | 読む (yomu) | 読みます (yomimasu) | 読んだ (yonda) | 読みました (yomimashita) |
The clear separation between ru-verbs and u-verbs provides a solid foundation for mastering Japanese conjugation, enabling more confident progress into more complex tenses and forms.