Since I personally focus on speaking Japanese and use romaji to learn, this post will only cover the spoken side; no hiragana, katakana, or kanji here. If you’re learning to read Japanese, I recommend using other resources or asking ChatGPT for guidance.
(Feel free to check out the r/languagelearning and r/LearnJapanese subreddits for extra resources or recommendations).
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💬 I’m still learning Japanese too, (on my journey from bronze to grandmaster), I document everything in my weekly language progress logs.
Every week I post a page with:
- A short speaking video or update
- My test assessment
- Notes and improvements
- What rank I’m at (from Bronze to Grandmaster)
👉 Check out the Language Progress Glossary Here
This is the third part of my Japanese past tense grammar series. In this post, I’ll be focusing on na-adjectives in both their past tense and negative past tense forms, all written in romaji, for learners who aren’t yet reading hiragana.
🔹 What Are Na-Adjectives?
Even though many of them use “na” when modifying a noun directly (like kirei na onna), the “na” disappears when used with the copula (“to be” words like desu, da, datta, etc.).
⚠️ Some na-adjectives, like kirei or yuumei, look like -i adjectives but aren’t!
If it doesn’t end in -i, and it’s not a noun, it’s likely a na-adjective.
If you’re not familiar with how to negate na-adjectives, check out my Japanese negation guide here:
👉 Japanese negations for -i and na adjectives
💡 How to Conjugate Na-Adjectives in the Past Tense
The na from these adjectives is dropped, and you’ll replace it with either:
- datta (for casual/informal past tense)
- deshita (for formal past tense)
Casual Past Tense (datta)
Conjugation:
→ na-adjective (drop na) + datta
(na → da → datta)
Examples:
- suki na → suki datta — To like → liked
- yuumei na → yuumei datta — Famous → was famous
- kirei na → kirei datta — Pretty/clean → was pretty/clean (irregular – ends in -i but is still a na-adjective)
Sentence examples:
- Hima datta kara, kino eiga kan ni ikimashita. – I had free time, so I went to the movie theater yesterday.
- Kino wa tokubetsu datta. Kyou wa muri. – Yesterday was special. Today is impossible.
- Ano yoru wa shizuka datta. – That night was quiet.
Formal Past Tense (deshita)
Conjugation:
→ na-adjective (drop na) + deshita
Examples:
- raku na → raku deshita — Easy/comfortable → was easy/comfortable
- majime na → majime deshita — Serious → was serious
- rippa na → rippa deshita — Excellent/splendid → was excellent/splendid
Sentence examples:
- Mou akirameta. Ore heta deshita. – I gave up. I was pretty bad at it.
- Daijoubu daijoubu. Ano basho wa anzen deshita. – Don’t worry, don’t worry. That place was safe.
- Doko ni ita no? Shinpai deshita! – Where were you? I was worried!
Negative Past Tense for Na-Adjectives
To make na-adjectives negative in the past tense:
Conjugation (casual):
→ na-adjective → ja nai → ja nakatta
So essentially, you take the present negative form, and turn nai → nakatta
Casual Negative Past (ja nakatta)
Examples:
- ijou na → ijou ja nakatta — Abnormal → was not abnormal
- sayaku na → sayaku ja nakatta — Worst → was not the worst
- honki na → honki ja nakatta — Serious → was not serious
Sentence examples:
- Kekkyoku, sore wa ijou ja nakatta. – In the end, it wasn’t anything unusual.
- Ano eiga wa sayaku ja nakatta. Tanoshikatta yo. – That movie wasn’t the worst. It was actually fun!
- Kare wa honki ja nakatta to omou. – I don’t think he was being serious.
Formal Negative Past (ja arimasen deshita)
To be more polite or formal, instead of using ja nai or ja nakatta, use:
Conjugation:
→ ja arimasen deshita
Examples:
- teinei na → teinei ja arimasen deshita — Polite → was not polite
- anzen na → anzen ja arimasen deshita — Safe → was not safe
- kantan na → kantan ja arimasen deshita — Easy → was not easy
Sentence examples:
- Ano hito wa amari teinei ja arimasen deshita. – That person was not very polite.
- Kesa no michi wa anzen ja arimasen deshita. – The road this morning was not safe.
- Shiken wa kantan ja arimasen deshita. – The test was not easy.
🌟 Final Thoughts
Na-adjective conjugation is straightforward once you memorize a few patterns:
| Tense | Casual | Formal |
|---|---|---|
| Past | datta | deshita |
| Negative Past | ja nakatta | ja arimasen deshita |
Mastering na-adjective conjugations in the past tense is simpler than it looks. Once you’re familiar with the patterns (datta, deshita, ja nakatta, ja arimasen deshita), you’ll start recognizing them in real conversations, even if you’re only learning in romaji.
And remember: Japanese isn’t like Chinese with strict tones, so slight pronunciation variations (like saying datta vs ta more softly) won’t usually change the meaning, especially in casual speech.
🧱 Why I Learn This Way
While I continue learning Japanese and other languages, I also make money online through beermoney apps. It’s not much, but it helps me feel like I’m turning my free time into something more productive and fun.
👇 Check out my glossaries below
💸 Beermoney Glossary:
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👉 Beermoney reviews
📈 Monthly Earnings Tracker:
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👉 Monthly earnings
🌍 Language Learning Glossary:
Curious what languages I’m learning? Check out my Language Learning Glossary for weekly progress updates. I post short speaking videos, track my progress, share my personal study notes, and break down the rank criteria I follow.
👉 Language progress