Meaning
偵 means to spy, scout, and investigate in secret. Picture a detective shadowing a suspect through the streets of Tokyo, or a military scout mapping enemy positions from a ridge in the dark. That disciplined, covert work of drawing out hidden information — patient, methodical, unseen — is exactly what this character captures.
In modern Japanese, 偵 appears in two essential compounds: 探偵 (detective) and 偵察 (reconnaissance). Criminal investigation and military operations are very different worlds. Both depend on the same quiet gathering of information that others want kept hidden.
Break 偵 apart and two components emerge. The left side is 亻, the person radical (ninben), marking it as something humans do. The right side is 貞 (tei), meaning upright, steadfast, or morally firm. Put them together and you get a person of unwavering, purposeful determination — moving quietly, watching carefully, closing in on the truth. That is the detective. That is the scout.
偵 has 11 strokes and belongs to the Joyo kanji list at the high-school and adult level (grade 8 in the extended classification). Its radical is 亻 (person, ninben), placing it alongside kanji like 働く (to work), 使う (to use), and 俳優 (actor). At N1 level, 偵 turns up in formal writing, news reports, and legal documents — and thanks to Detective Conan, it is one of the more recognizable N1 kanji in popular culture.
Readings
On'yomi (音読み) — Chinese-derived readings
偵 has one on'yomi: テイ (TEI). It almost never stands alone as a word, so mastering this single reading unlocks every compound that matters.
テイ (TEI) — found across investigation and military vocabulary:
- 探偵 (tantei) — detective, private investigator
- 偵察 (teisatsu) — reconnaissance, scouting
- 内偵 (naitei) — undercover investigation, internal inquiry
Kun'yomi (訓読み) — Native Japanese readings
偵 has no standard kun'yomi in modern Japanese. The verb うかが・う (ukagau — to spy out, to reconnoiter) occasionally appears with this character in archaic texts, but it is absent from modern dictionaries and JLPT study materials alike.
This gap is common for N1 kanji borrowed from Chinese to fill specialized vocabulary needs. 偵 works as a building block in compound words, not as a standalone word. Put your study effort into the reading テイ and the key compounds below.
Common Words & Compounds
Every compound here uses the on'yomi テイ. The vocabulary falls into two groups: detective fiction and criminal investigation on one side, military and intelligence operations on the other.
Detective and Criminal Investigation:
- 探偵 (tantei) — detective, private investigator; the most common word containing 偵
- 名探偵 (meitantei) — great detective, famous detective; seen in the title Meitantei Conan
- 私立探偵 (shiritsu tantei) — private detective, private eye
- 探偵小説 (tantei shousetsu) — detective novel, mystery fiction
- 内偵 (naitei) — undercover investigation; secret inquiry conducted by police
- 偵知 (teichi) — detection, discovery through investigation
Military and Intelligence:
- 偵察 (teisatsu) — reconnaissance, scouting; gathering military intelligence
- 偵察機 (teisatsuki) — reconnaissance aircraft, spy plane
- 偵察衛星 (teisatsu eisei) — reconnaissance satellite, spy satellite
- 偵察部隊 (teisatsu butai) — reconnaissance unit, scout squad
- 偵察活動 (teisatsu katsudou) — reconnaissance activities, scouting operations
Example Sentences
彼は有名な名探偵だ。
Kare wa yuumei na meitantei da.
He is a famous great detective.
私立探偵を雇って夫を調べてもらった。
Shiritsu tantei wo yatotte otto wo shirabete moratta.
I hired a private detective to investigate my husband.
軍は敵の基地に偵察を送った。
Gun wa teki no kichi ni teisatsu wo okutta.
The military sent a reconnaissance unit to the enemy base.
偵察機が国境付近を飛んでいた。
Teisatsuki ga kokkyou fukin wo tonde ita.
A reconnaissance aircraft was flying near the border.
警察は内偵を続け、ついに証拠を掴んだ。
Keisatsu wa naitei wo tsuzuke, tsui ni shouko wo tsukanda.
The police continued the undercover investigation and finally obtained evidence.
彼女は探偵小説を読むのが好きだ。
Kanojo wa tantei shousetsu wo yomu no ga suki da.
She likes to read detective novels.
偵察衛星が貴重な情報を送ってきた。
Teisatsu eisei ga kichou na jouhou wo okutte kita.
The reconnaissance satellite sent back valuable information.
その探偵は鋭い観察力で犯人を特定した。
Sono tantei wa surudoi kansatsuryoku de hannin wo tokutei shita.
That detective identified the criminal with sharp observation skills.
敵の動向を偵察するために特殊部隊が派遣された。
Teki no doukou wo teisatsu suru tame ni tokushu butai ga haken sareta.
Special forces were dispatched to scout the enemy's movements.
Memory Tip
Break 偵 into its two parts: 亻 (a person) on the left, 貞 (steadfast, upright) on the right. A person of stubborn, quiet determination — that is the detective. That is the scout. They never rush; they watch, they wait, building a picture one observation at a time.
Want a pop-culture hook? The kanji sits right in the title 名探偵コナン (Detective Conan), Japan's most iconic mystery franchise. Young Conan never panics — he observes, deduces, and patiently corners the truth. That patience, that precision, is what 偵 means.