Meaning
投 means to throw. At its most basic, it's a physical act — a pitcher releasing a fastball, a fisherman casting a net, a child skipping stones across a pond. The kanji captures that moment of deliberate release.
Over time, 投 expanded beyond the physical. Think of dropping a stone into deep water: it goes in and doesn't come back easily. 投 took on the same logic for money and effort. That's how 投資 (tōshi), investment, got its name — you're throwing capital into something, hoping it returns with interest.
Structurally, 投 pairs the hand radical 扌 (a simplified 手, hand) on the left with 殳 (shū) on the right — an old character depicting a hand gripping a striking implement. Seven strokes total. Japanese schools introduce it in Grade 3, which gives you a sense of how often it comes up.
Classical Chinese and older literary Japanese also used 投 to mean surrendering — throwing oneself at another's mercy. That sense survived into modern Japanese in words like 投降 (tōkō).
Readings
On'yomi (音読み) — Chinese-derived readings
The on'yomi is トウ (tō). Most compound words use this reading. It shows up constantly in formal writing, news, and business contexts. Like many on'yomi, トウ traces back to Middle Chinese pronunciation, absorbed during Japan's large-scale borrowing of Chinese vocabulary.
- 投票 (tōhyō) — voting, casting a ballot
- 投資 (tōshi) — investment
- 投手 (tōshu) — pitcher (in baseball)
- 投稿 (tōkō) — submission, post (online or print)
- 投入 (tōnyū) — throwing in, injection of resources
- 投下 (tōka) — dropping, throwing downward
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi is な.げる (nageru) — the native Japanese verb for throwing. In the notation な.げる, the dot marks where the kanji ends and the okurigana begins. Use this reading when 投 acts as a standalone verb or heads a compound verb.
- 投げる (nageru) — to throw, to pitch
- 投げかける (nagekakeru) — to throw toward, to direct (a question)
- 投げ捨てる (nagesuteru) — to throw away, to discard
- 投げやり (nageyari) — half-hearted, careless (lit. throwing a spear carelessly)
Common Words & Compounds
投 turns up across sports, finance, media, and daily life. Here are the key compounds by category.
Sports & Physical Action
- 投手 (tōshu) — pitcher (baseball)
- 投球 (tōkyū) — pitching, throwing a ball
- 投網 (toami) — casting net (for fishing)
- 投げ技 (nagewaza) — throwing techniques (in martial arts)
Finance & Economics
- 投資 (tōshi) — investment
- 投資家 (tōshika) — investor
- 投入 (tōnyū) — input of capital or resources
Media, Communication & Politics
- 投票 (tōhyō) — voting
- 投稿 (tōkō) — post, submission (article, online content)
- 投書 (tōsho) — letter to the editor, written complaint
Other Common Uses
- 投影 (tōei) — projection (of light or image)
- 投薬 (tōyaku) — administration of medicine
- 投降 (tōkō) — surrender, giving oneself up
Example Sentences
彼はボールを強く投げた。
Kare wa bōru wo tsuyoku nageta.
He threw the ball hard.
選手たちは投票でキャプテンを決めた。
Senshu-tachi wa tōhyō de kyaputen wo kimeta.
The players voted to decide their captain.
彼女はブログに毎日投稿している。
Kanojo wa burogu ni mainichi tōkō shite iru.
She posts to her blog every day.
会社は新しい事業に多額の資金を投入した。
Kaisha wa atarashii jigyō ni tagaku no shikin wo tōnyū shita.
The company poured a large sum into the new venture.
父は株に投資するのが好きだ。
Chichi wa kabu ni tōshi suru no ga suki da.
My father likes investing in stocks.
医師は患者に薬を投与した。
Ishi wa kanja ni kusuri wo tōyo shita.
The doctor administered medicine to the patient.
子供たちは川に石を投げて遊んでいた。
Kodomo-tachi wa kawa ni ishi wo nagete asonde ita.
The children played by throwing stones into the river.
敵の軍はついに投降した。
Teki no gun wa tsui ni tōkō shita.
The enemy forces finally surrendered.
彼は難しい問題を私に投げかけた。
Kare wa muzukashii mondai wo watashi ni nagekaketa.
He threw a difficult question at me.
Memory Tip
Picture a baseball pitcher mid-windup. The hand radical 扌 on the left is the throwing hand. On the right, 殳 shows an ancient figure gripping a tool — poised to strike or release.
Look at 投球 (pitch), 投票 (vote), 投資 (invest): in every case, something leaves the hand with intent. The kanji carries that momentum in its shape.