Telling Time: 時 and 分

Telling time in Japanese uses two counters stacked together: 〜時（じ） for the hour ("o'clock") and 〜分（ふん／ぷん） for the minutes, with 半（はん） as a handy shortcut for "half past." Neither counter is fully regular. 時 has three irregular hour-readings you'll use constantly, and 分 has more sound changes than almost any counter in the language — which is exactly why it's the perfect place to drill the geminate-and-voicing rule until it's automatic.

The hours: 〜時

Take a Sino number and add 〜じ. Three of the twelve are irregular, and they are the three you must nail.

The three to burn in:

• 4時 = よじ — uses よ, not the usual よん and definitely not し. Never shi-ji, never yon-ji.
• 7時 = しちじ — uses しち, not なな. So shichi-ji, not nana-ji.
• 9時 = くじ — uses く, not きゅう. So ku-ji, not kyū-ji.

"What time?" is 何時（なんじ） nan-ji.

The minutes: 〜分

Now the workhorse. 分 begins with an h-type sound, so it is a magnet for both euphonic forces — gemination (a held っ + a hardened ぷ) after 1, 6, 8, 10, and voicing-to-p after ん (3, 何). The result is an alternation between soft ふん and hard ぷん that runs the whole way up.

Read the pattern, don't memorize twelve isolated words. ぷん (hard p) appears after 1, 3, 4, 6, 8, 10 and 何 (何分 nanpun); ふん (soft f) stays after the "quiet" numbers 2, 5, 7, 9. That split is the two forces in miniature:

• 1, 6, 8, 10 geminate: a small っ appears and f hardens to p → いっぷん, ろっぷん, はっぷん, じゅっぷん.
• 3, 何 end in ん, which voices/hardens the following f to p → さんぷん, なんぷん.
• 4 is the surprise: normally a "quiet" number, but 分 is greedy and takes ぷん here too → よんぷん.
• Tens follow the ones: 15分 じゅうごふん (jū-go-fun), 30分 さんじゅっぷん (san-juppun), 45分 よんじゅうごふん (yon-jū-go-fun).

The full logic behind this alternation — and the fact that 分 is the counter most linguists reach for to illustrate it — lives on Counter Sound Changes: The Master Pattern. If you can conjugate 分 cold, most other counters will feel easy.

Putting hours and minutes together — and 半 for half past

To give a full time, just say the hour, then the minutes: hour + 時 + minutes + 分. No word for "and," no "past," no "o'clock" filler — Japanese states it in one clean stream.

For the very common "half past," you don't say 三十分 — you use 半（はん） han, tacked straight onto the hour:

For morning and afternoon, prefix 午前（ごぜん） "AM" or 午後（ごご） "PM" — Japan uses a 12-hour clock in speech even though timetables print 24-hour times.

Time points take に

A clock time is a specific point in time, so it takes the particle に when it marks when something happens: 九時に, 四時半に, 七時十五分に. This is the same に used for dates (四日に) and weekdays (月曜日に) — see に: Specific Points in Time. Vague time words like 今 (ima, "now") or 朝 (asa, "morning") do not take に, but a number-on-the-clock always can.

時 (o'clock) vs 時間 (hours of duration)

Don't confuse the hour of the clock with a span of hours. 三時 san-ji is "3 o'clock" (a point); 三時間 san-jikan is "three hours" (a length). Add 間（かん）and you switch from telling time to measuring it — exactly parallel to how 三日 (a date) becomes 三日間 (a three-day span).

Common mistakes

Reading 四時 with the default shi is the classic error — and shi also sounds like 死 ("death"), which is a second reason Japanese avoids it. It's always よじ.

Since 9 is usually きゅう, learners produce kyū-ji. But the hour, the month (九月 くがつ), and the day (九日 ここのか) all favor く. Nine o'clock is くじ.

Leaving 分 as soft fun after 3 is the most common minutes error. The ん forces it to ぷん: さんぷん. The same hardening gives you いっぷん, ろっぷん, はっぷん, じゅっぷん.

半 already means "thirty minutes past," so you never add 分 to it. It's simply 時 + 半.

Key takeaways

• Hours are number + 〜時, with three irregulars: 4時 よじ, 7時 しちじ, 9時 くじ (and 何時 なんじ for "what time").
• Minutes alternate ふん / ぷん: hard ぷん after 1, 3, 4, 6, 8, 10, 何; soft ふん after 2, 5, 7, 9 — the geminate-and-voicing rule in its purest form.
• Build a full time as hour + minutes; use 半（はん） for "half past" (四時半 = 4:30) and 午前／午後 for AM/PM.
• Clock times take に to mark when something happens (九時に).
• Keep 時 (o'clock, a point) apart from 時間 (hours, a duration): 三時 ≠ 三時間.