Meaning
Whether you are tapping an IC card at a ticket gate or unboxing a delivery, you will see 開 everywhere in Japan. While it primarily means 'to open,' its usage spans from sliding a physical door to the metaphorical 'opening' of a new era or business. For N4 learners, the real challenge lies in distinguishing its many different verb forms. Mastering this character is a major step toward intermediate fluency because it appears in so many daily contexts.
The character's design tells a clear story. The outer frame is the radical 門 (gate), representing traditional swinging doors. Inside sits 幵, which originally depicted two hands holding a horizontal bolt. Imagine someone sliding that wooden bolt aside to let the doors swing wide. This 12-stroke kanji is taught to 3rd graders and remains one of the most functional characters in the language.
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi reading is カイ (kai). You will usually find this reading in formal compound words, known as jukugo. It often describes events, business operations, or the public release of information. On signs, you might see it paired with 'close' to show business hours.
Examples of カイ in use:
- 開始 (kaishi) — Start / Commencement
- 開店 (kaiten) — Opening of a store
- 開放 (kaihou) — Opening up / Liberalization
Kun'yomi (訓読み) — Native Japanese readings
The native readings are where things get interesting. 開 has several versions depending on what is being opened and how. あ.ける (akeru) is transitive, meaning you open something like a window. あ.く (aku) is intransitive, meaning something opens by itself, like an automatic door. Finally, ひら.く (hiraku) is used for unfolding things like books or umbrellas, or for abstract actions like opening a bank account.
Examples of native readings:
- 開ける (akeru) — To open (e.g., a jar, a window, your eyes)
- 開く (aku) — To be open (e.g., the shop is open, the door opens)
- 開く (hiraku) — To open/unfold (e.g., a flower, a book, an umbrella, a laptop)
Common Words & Compounds
To understand 開, you need to see it in different environments. Notice how the 'KAI' reading dominates formal vocabulary, while 'a' and 'hira' appear in physical, everyday actions.
Business and Public Life:
- 公開 (koukai) — Open to the public / Released (like a movie)
- 開業 (kaigyou) — Starting a business / Opening a practice
- 開会 (kaikai) — Opening of a meeting or ceremony
- 全開 (zenkai) — Opening fully (e.g., windows or throttle)
Science and Development:
- 開発 (kaihatsu) — Development (e.g., software or urban planning)
- 開拓 (kaitaku) — Reclamation / Pioneering / Opening up new land
- 未開発 (mikaihatsu) — Undeveloped
Physical and Daily Actions:
- 開閉 (kaihei) — Opening and shutting (often seen on elevator buttons)
- 幕を開ける (maku wo akeru) — To open the curtain (or start a new phase)
- 穴を開ける (ana wo akeru) — To make/drill a hole
- 道を開く (michi wo hiraku) — To clear a path / To pave the way
Example Sentences
すみませんが、窓を開けてもいいですか。
sumimasen ga, mado wo akete mo ii desu ka.
Excuse me, but may I open the window?
このドアは、ボタンを押すと開きます。
kono doa wa, botan wo osu to akimasu.
This door opens when you press the button.
みんなで教科書の２０ページを開きましょう。
minna de kyoukasho no nijuu peeji wo hirakimashou.
Let's all open our textbooks to page 20.
テストの開始時間は午前９時です。
tesuto no kaishi jikan wa gozen kuji desu.
The start time for the test is 9:00 AM.
あそこの新しいパン屋さんはもう開店しましたか。
asoko no atarashii panya-san wa mou kaiten shimashita ka.
Has that new bakery over there opened for business yet?
テニススクールに入るために、銀行口座を開きました。
tenisu sukuuru ni hairu tame ni, ginkou kouza wo hirakimashita.
I opened a bank account in order to join the tennis school.
このソフトは、まだ開発の途中です。
kono sofuto wa, mada kaihatsu no tochuu desu.
This software is still in the middle of development.
その映画は、いよいよ来週公開されます。
sono eiga wa, iyoiyo raishuu koukai saremasu.
That movie will finally be released next week.
Related Kanji
- 走 — Run, Move fast (Kanji N4)
- 思 — To Think, Feel, Imagine (Kanji N4)
- 死 — Death, Die (Kanji N4)
- 業 — Business, Vocation, Arts, Karma (Kanji N4)
- 貸 — To lend, rent, or loan (Kanji N4)
- 知 — Know, Wisdom, Intellect (Kanji N4)
Memory Tip
Focus on the visual: see the two hands (幵) reaching out to pull the bolt inside a massive set of temple gates (門). If the bolt is moved, the way is open. It is a physical, action-oriented character that literally shows you the process of unbarring a door.