furui-vs-mukashi

Both ふるい (furui) and むかし (mukashi) relate to the past and to things being old — but they work very differently in Japanese. ふるい is an adjective describing a physical object that has aged. むかし is a noun (and adverb) that refers to a period of time in the past, the “old days,” or long ago. You can use ふるい to describe an old photograph, but you use むかし to say “back in the day.” Confusing them will produce unnatural Japanese — this guide makes the distinction permanent.

At a Glance: ふるい vs. むかし

ふるい (古い) — Old as a Describable Quality

ふるい is an い-adjective that describes a specific object or thing as having existed for a long time — worn, aged, or outdated. You can think of it as the quality of being old. The kanji 古 also appears in 古典 (koten — classical / ancient literature), 古代 (kodai — ancient times), and 中古 (chuuko — used/secondhand).

Example 1 — an old object:

この自転車はとても古い。
Kono jitensha wa totemo furui.
This bicycle is very old.

Example 2 — an old building:

古いお寺を見学した。
Furui otera wo kengaku shita.
I visited an old temple.

Example 3 — outdated thinking:

古い考え方はもう通用しない。
Furui kangaekata wa mou tsuuyou shinai.
Outdated ways of thinking no longer work.

むかし (昔) — The Old Days and Long Ago

むかし is a noun and temporal adverb meaning “long ago,” “in the old days,” or “back then.” It points to a vague time in the past — it could be decades, centuries, or just a personal “back in my day.” It does not describe an object’s age; it locates a story or fact in time. Fairy tales in Japanese famously begin with むかし、むかし (mukashi mukashi — once upon a time).

Example 1 — once upon a time (fairy tale opener):

むかし、むかし、あるところに…
Mukashi, mukashi, aru tokoro ni…
Once upon a time, in a certain place…

Example 2 — in the old days / back then:

むかしはここに大きな木があった。
Mukashi wa koko ni ookina ki ga atta.
In the old days, there was a big tree here.

Example 3 — personal past:

むかし、よくこの公園で遊んだ。
Mukashi, yoku kono kouen de asonda.
I used to play in this park a lot back in the day.

The Core Distinction: Adjective vs. Time Word

The fundamental difference is grammatical category:

Notice: when むかし modifies a noun, it needs の: むかしの音楽 (mukashi no ongaku — music from the old days). ふるい can modify a noun directly without の.

Common Expressions with むかし

Decision Flowchart: ふるい or むかし?

Are you talking about something old / from the past?
                     |
                     v
Is it an OBJECT / THING that has aged?
          |                      |
         YES                     NO (it's a TIME PERIOD
          |                      or "back in the day")
          v                      |
       ふるい                     v
      (furui)                 むかし
      古い                    (mukashi)
                              昔

Examples:
- Old camera → 古いカメラ (ふるい)
- Long ago → むかし (むかし)
- Outdated method → 古い方法 (ふるい)
- In my childhood days → むかしは (むかし)

Quick Quiz — Test Yourself!

Choose ふるい or むかし for each sentence.

Q1. This phone is very old.
このスマホはとても＿＿＿。
Kono sumaho wa totemo ___.

Answer: ふるい (furui) — 古い
Reason: The phone is an object being described as aged — ふるい is correct. Note it comes in predicate position here (after は).

Q2. Long ago, this area was a forest.
＿＿＿、この辺りは森だった。
___, kono atari wa mori datta.

Answer: むかし (mukashi) — 昔
Reason: The sentence refers to a time period in the past, not an object’s age. むかし opens the sentence as a temporal adverb.

Q3. I love listening to music from the old days.
＿＿＿の音楽を聴くのが大好きだ。
___ no ongaku wo kiku no ga daisuki da.

Answer: むかし (mukashi) — 昔の音楽
Reason: “Music from the old days” is むかしの音楽. Note the の connecting むかし to the noun 音楽.

Q4. We stayed at a charming old inn.
＿＿＿い旅館に泊まった。
___i ryokan ni tomatta.

Answer: ふる (furu-) → 古い旅館
Reason: The inn is a physical place being described as old. ふるい directly modifies the noun 旅館 before it.

Q5. He has been playing the piano since long ago.
彼は＿＿＿からピアノを弾いている。
Kare wa ___ kara piano wo hiite iru.

Answer: むかし (mukashi) — 昔から (since long ago)
Reason: 昔から (mukashi kara) is a set expression meaning “from long ago / since old times.” This is a time reference, not describing an object.

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