godan verb (-ku), intransitive verb, transitive verb
Basic physical sense: open something closed, or for something to open out. Often used with things like books, packages, doors, windows, and lids; transitive and intransitive uses both exist.
教科書を三十二ページに開いてください。
Please open your textbook to page thirty-two.
彼
He opened the package and checked what was inside.
godan verb (-ku), intransitive verb, transitive verb
bloom; unfold; spread out; flare
Used when petals, buds, fans, maps, or shapes open outward. Also covers the clothing/shape use where a skirt or hem flares out.
朝になると、庭のつぼみがゆっくり開いた。
In the morning, the buds in the garden slowly opened.
裾が外側に開いたスカートを選んだ。
She chose a skirt with a hem that flares outward.
godan verb (-ku), intransitive verb, transitive verb
open for business
Intransitive use for a shop, bank, office, or similar place beginning business for the day.
店がひらくまで、駅前で待った。
I waited in front of the station until the shop opened.
godan verb (-ku), intransitive verb, transitive verb
widen; become wide; be spaced apart
Used for gaps, intervals, differences, or body parts moving farther apart. Common patterns include 差が開く, 間隔が開く, and 足を開く.
先頭との差が少しずつ開いてきた。
The gap with the leader gradually widened.
足を肩幅に開いて立ってください。
Please stand with your feet shoulder-width apart.
godan verb (-ku), transitive verb
Transitive use with meetings, parties, exhibitions, classes, press conferences, and similar organized events.
来週、臨時の会議を開く。
We will hold an extraordinary meeting next week.
godan verb (-ku), transitive verb
found; establish; open a new business; set up
Transitive use for starting or establishing something such as a shop, office, school, sect, dynasty, or organization.
彼女は去年、駅前に小さな店を開いた。
Last year she opened a small shop in front of the station.
godan verb (-ku), transitive verb
open ports or borders
Used for making a port, border, country, market, or similar boundary accessible to outsiders.
政府は国境を外国人旅行者に開いた。
The government opened the border to foreign travelers.
godan verb (-ku), transitive verb
open an account
Transitive financial use, typically in the phrase 口座を開く. 開設する is a more formal alternative.
留学前に日本の銀行で口座を開いた。
Before studying abroad, I opened an account at a Japanese bank.
godan verb (-ku), transitive verb
open up land or a route; clear; develop
Used for making new land, a road, a path, a market, or a field of activity usable. The spelling 拓く is especially associated with this 'open up/develop' sense.
See also: 拓く
彼らは山に新しい道を開いた。
They opened up a new path through the mountain.
godan verb (-ku), transitive verb
open a file
Computing use for opening a file, folder, app window, link, or similar digital item.
添付ファイルを開く前に、送信者を確認してください。
Before opening the attached file, check the sender.
godan verb (-ku), transitive verb
extract a root; reduce an equation
Technical mathematical use; it is uncommon in ordinary modern conversation and may be replaced by more explicit expressions such as 平方根を求める or 式を整理する.
古い数学の説明では、「16を平方に開くと4になる」と言うことがある。
In older mathematical explanations, one may say, 'extracting the square root of 16 gives 4.'
ここで「方程式を開く」とは、式を整理して簡単な形にするという意味だ。
Here, 'opening the equation' means rearranging it into a simpler form.
godan verb (-ku), transitive verb
cut open a fish
Cooking use, especially 魚を開く: to split a fish open flat for drying, grilling, or preparation.
アジを開いて干物にした。
I cut open the horse mackerel and made it into dried fish.
godan verb (-ku), transitive verb
write kanji in kana; spell out in hiragana
Editorial and writing-related use: converting kanji into hiragana, often to make text easier to read or to follow a style guide.
小学生向けの記事では、難しい漢字をひらがなに開くことがある。
In articles for elementary school students, difficult kanji are sometimes written out in hiragana.
godan verb (-ku), intransitive verb
open up into poor posture; slacken
Sports coaching term, especially in baseball, golf, and similar movements. 体が開く or 肩が開く means the body or shoulders open too early, weakening the form.
投球のときに肩が早く開くと、球が外に流れやすい。
If your shoulder opens too early when pitching, the ball tends to drift outside.
godan verb (-ku), intransitive verb
extend in Go
Only with reading ヒラく
Go term usually written ヒラく. It means to extend from a stone or position, especially along the side of the board.
See also: ヒラキ
布石で黒は右辺にヒラいた。
In the opening, Black extended on the right side.