Meaning
The kanji 速 (soku, hayai) is all about speed, quickness, and promptness. It's a crucial character in Japanese for describing velocity, rapidity, and the swiftness of actions or processes. This kanji is part of the JLPT N3 curriculum. Taught to third graders in Japanese elementary school, it's a fundamental character vital for everyday communication.
Visually, 速 is made up of two main components: the radical 辶 (しんにょう, shinnyou) on the left, and 束 (たば, taba) on the right. The 辶 radical, often called the "road" or "walk" radical, inherently suggests movement, motion, or a path. This component is common in kanji related to travel, advance, or retreat. On the other hand, the 束 component typically means "bundle" or "tie." Here, it primarily acts as a phonetic element, suggesting the sound "soku." It also contributes semantically, hinting at something quickly gathered or tied up. When these two elements combine, 速 powerfully conveys the idea of moving swiftly along a path or in a specific direction. Imagine a bundle being carried quickly along a road, or an action being completed in a tied-up, efficient, and therefore fast, manner.
This kanji has 10 strokes and is a Grade 3 Kyouiku Kanji, meaning Japanese third graders learn it. Its simple structure and clear components make it relatively easy to remember, especially once you connect movement (辶) with swiftness (束, which provides both phonetic and semantic hints).
Readings
On'yomi (音読み) — Chinese-derived readings
On'yomi are readings adopted from Chinese pronunciations. You'll typically find them when a kanji is part of a compound word (熟語, 熟語). For 速, the main on'yomi is ソク (soku).
ソク (soku): This reading appears frequently in words describing speed, velocity, or the act of quickening.
速度 (sokudo) — This means "speed" or "velocity." It combines 速 (speed) with 度 (degree, rate) and is often used for physical speed measurements in scientific or technical contexts.
高速 (kōsoku) — Meaning "high speed," this compound combines 高 (high) with 速 (speed). It's commonly seen in terms like 高速道路 (kōsoku dōro, expressway) or 高速列車 (kōsoku ressha, high-speed train).
早速 (sassoku) — This word means "immediately," "at once," or "without delay." The first kanji, 早 (satsu), also implies early or quick. Together, they emphasize promptness in action.
Kun'yomi (訓読み) — Native Japanese readings
Kun'yomi are native Japanese readings. You'll often see them when the kanji appears alone or is followed by okurigana (送り仮名), which are kana suffixes that complete the word. 速 has several key kun'yomi.
はや.い (haya.i): This is the most common adjective form, meaning "fast" or "quick." While it can sometimes mean "early," 早 is more typically used for that meaning. It describes something that moves or happens with speed.
速い (hayai) — Fast, quick. Example: 彼は足が速い (kare wa ashi ga hayai), "He is a fast runner."
動作が速い (dōsa ga hayai) — Having quick movements, agile.
はや.まる (haya.maru): This intransitive verb means "to be quickened," "to be hastened," or "to speed up." It describes when something's speed increases on its own or due to an external factor.
出発が速まる (shuppatsu ga hayamaru) — The departure is hastened/speeds up.
心臓の鼓動が速まる (shinzō no kodō ga hayamaru) — One's heartbeat quickens, often due to excitement or fear.
はや.める (haya.meru): This is the transitive counterpart to はやまる, meaning "to quicken," "to hasten," or "to accelerate." It describes actively making something faster.
速度を速める (sokudo o hayameru) — To quicken one's speed, to accelerate.
歩みを速める (ayumi o hayameru) — To quicken one's pace, to walk faster.
すみ.やか (sumi.yaka): This adjectival noun is often used with に to form an adverbial phrase meaning "swiftly," "promptly," or "rapidly." It emphasizes an action or response's quickness and promptness, often implying efficiency or necessity.
速やかに対応する (sumiyaka ni taiō suru) — To respond promptly and without delay.
速やかな行動 (sumiyaka na kōdō) — Swift and decisive action.
Common Words & Compounds
The kanji 速 appears in many practical and widely used Japanese words, covering various aspects of speed, promptness, and efficiency. Here are some common examples, grouped by theme:
General Speed & Velocity
速度 (sokudo) — Speed, velocity. (e.g., 車の速度 - car speed, 光の速度 - speed of light)
高速 (kōsoku) — High speed. (e.g., 高速バス - highway bus, 高速インターネット - high-speed internet)
低速 (teisoku) — Low speed. (e.g., 低速運転 - slow driving, 低速回転 - slow rotation)
快速 (kaisoku) — Rapid, express (train, bus). Used for trains that skip some stations to travel faster. (e.g., 快速列車 - rapid service train)
迅速 (jinsoku) — Swift, prompt, quick. Often implies an urgent need for quick action. (e.g., 迅速な対応 - prompt response, 迅速な判断 - quick judgment)
Time & Rate
早速 (sassoku) — Immediately, at once, without delay. (e.g., 早速始める - to start immediately, 早速連絡する - to contact right away)
時速 (jisoku) — Speed per hour. (e.g., 時速１００キロ - 100 kilometers per hour)
秒速 (byōsoku) — Speed per second. (e.g., 秒速５メートル - 5 meters per second)
Communication & Delivery
速報 (sokuhō) — Breaking news, flash report, prompt report. (e.g., 地震速報 - earthquake flash report, ニュース速報 - news flash)
速達 (sokutatsu) — Express delivery, special delivery. (e.g., 速達便 - express mail service, 速達で送る - to send by express mail)
速記 (sokki) — Shorthand, stenography. (e.g., 速記術 - stenography technique, 速記者 - shorthand writer)
Nature & Physics
音速 (onsoku) — Speed of sound. (e.g., 音速を超える - to break the sound barrier)
光速 (kōsoku) — Speed of light. (e.g., 光速に近い - close to the speed of light)
風速 (fūsoku) — Wind speed. (e.g., 最大風速 - maximum wind speed, 風速計 - anemometer)
Example Sentences
この電車はとても速いです。
Kono densha wa totemo hayai desu.
This train is very fast.
彼は足が速いので、マラソン選手に向いています。
Kare wa ashi ga hayai node, marason senshu ni muite imasu.
He is a fast runner, so he is suited to be a marathon athlete.
高速道路を使うと、もっと早く着けます。
Kōsoku dōro o tsukau to, motto hayaku tsukemasu.
If you use the expressway, you can arrive much faster.
テストの結果を速報でお知らせします。
Tesuto no kekka o sokuhō de oshirase shimasu.
We will inform you of the test results via a flash report.
速達便で書類を送ったので、明日には届くはずです。
Sokutatsubin de shorui o okutta node, ashita ni wa todoku hazu desu.
I sent the documents by express mail, so they should arrive tomorrow.
出発時間が速まるかもしれないので、気をつけてください。
Shuppatsu jikan ga hayamaru kamoshirenai node, ki o tsukete kudasai.
The departure time might be hastened, so please be careful.
もっと効率的に仕事を進めるために、作業速度を速めることにしました。
Motto kōritsuteki ni shigoto o susumeru tame ni, sagyō sokudo o hayameru koto ni shimashita.
To proceed with work more efficiently, I decided to quicken the work pace.
この問題に対しては、速やかに対応する必要があります。
Kono mondai ni taishite wa, sumiyaka ni taiō suru hitsuyō ga arimasu.
It is necessary to respond promptly to this problem.
ランニングマシンの速度を上げて、運動量を増やしました。
Ranningu mashin no sokudo o agete, undōryō o fuyashimashita.
I increased the treadmill's speed and increased my workout volume.
Memory Tip
To remember 速, try visualizing its components: 辶 (shinnyou) and 束 (taba). The 辶 radical, which looks like a winding road or path, immediately brings to mind movement or travel. The 束 component means "bundle" or "tie." Imagine a runner, carrying a tightly tied "bundle" (束) on their back, moving "swiftly" (速) along a "path" (辶). The "bundle" implies efficiency and readiness, contributing to the idea of speed and a lack of hindrance. Alternatively, think of "tying up" (束) a task "quickly" (速) so you can get "on your way" (辶). The key lies in combining movement with something done efficiently or compactly, leading to swiftness. Remember: a bundle on the road moves fast!