noun
one shot; one round; one explosion
Counts a single discharge of a firearm, a single explosion, or a single charge of ammunition.
犯人は一発だけ発砲した。
The criminal fired only one shot.
その爆弾は一発で建物を破壊した。
The bomb destroyed the building with one explosion.
noun
one blow; one punch; one hit
Refers to a single strike, punch, or hit, often in fighting or sports.
彼は一発のパンチで相手を倒した。
He knocked down his opponent with one punch.
noun
Baseball term for a home run; often used in the phrase 一発を放つ.
四番打者が一発を放ち、試合を決めた。
The cleanup hitter hit a home run and decided the game.
noun, adverb
one try; one attempt; single shot
Used for doing something in a single attempt, often with the nuance of giving it one shot or trying once. Can be used adverbially as 一発で.
一発で試験に合格した。
I passed the exam on my first try.
この問題は一発で解決できる。
We can solve this problem in one go.
noun
ippatsu (mahjong)
Mahjong term: winning on the first go-around after declaring rīchi. A specific yaku.
See also: 立直 (リーチ)
リーチ一発で上がった。
I won with an ippatsu after declaring rīchi.
noun
ippatsu (karuta)
Abbreviation of 送り一発; in competitive karuta, taking a card immediately after sending it. Rare outside the game context.
See also: 送り一発
送り一発は、競技かるたの高度な技です。
Okuri-ippatsu is an advanced technique in competitive karuta.
一撃 also means a single blow or hit, but is more literary and often used in dramatic or martial contexts, while 一発 is broader and more colloquial.
A compound meaning 'a single blow reversal' or 'comeback from behind with one move'; uses 一発 in the sense of a decisive single action.
Compound of 一 (one) and 発 (counter for shots, explosions, etc.). The reading いっぱつ is a regular sound change from いちはつ.