Meaning
双 means pair, couple, both, and twin. It describes two things that naturally belong together — a matched set, two of a kind, or two sides of the same whole. This paired sense shows up in every compound, from the everyday word for twins (双子) to the formal phrase 双方 (both parties) in contracts and negotiations.
Structurally, 双 is an ideograph (会意文字, kaii moji) — a character built by combining two simpler symbols to express a new concept. It stacks two copies of 又 (また, mata), which originally depicted a right hand reaching out or grasping. Two identical hands placed side by side suggest a matching pair — symmetry made visible in the character's shape.
In traditional Chinese script and older Japanese texts, this was written as 雙, a more elaborate form with the radical for "bird" (隹) doubled, evoking two birds perched side by side. Modern Japanese simplified this to the doubled 又 structure. Worth noting: modern simplified Chinese also uses 双, making this one of the rare cases where Japanese shinjitai and simplified Chinese are identical.
双 has 4 strokes and is a grade 8 (high school) joyo kanji. Its radical is 又 (mata), meaning "again" or "also," which in ancient scripts depicted the right hand. The character appears regularly in formal writing, academic language, and literary contexts whenever duality or matched sets are involved.
Readings
On'yomi (音読み) — Chinese-derived readings
ソウ (sō) is the primary on'yomi, derived from the Middle Chinese pronunciation. It appears almost exclusively in compound words (熟語, jukugo) and is the reading you'll encounter most in N2-level texts. Formal, academic, and literary contexts all favor this reading.
Examples using ソウ:
- 双方 (sōhō) — both parties, both sides
- 双眼鏡 (sōgankyō) — binoculars (literally "both-eye instrument")
- 双肩 (sōken) — both shoulders
- 双璧 (sōheki) — two outstanding individuals or things, "both gems"
- 双曲線 (sōkyokusen) — hyperbola (mathematics)
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi ふた (futa) is the native Japanese word for "two" or "pair." It appears in a small set of native compounds. Note that in 双子, the final syllable ご is a suffix meaning "child," and the compound reads ふたご rather than ふたこ due to rendaku (sequential voicing).
Examples using ふた:
- 双子 (futago) — twins
- 双葉 (futaba) — twin leaves, seedling sprout, cotyledon
- 双六 (sugoroku) — traditional Japanese board game (irregular/historical reading)
Common Words & Compounds
双 turns up across many registers — daily speech, formal writing, academic terminology, and cultural references. The most useful compounds are organized below by theme.
People and Relationships:
- 双子 (futago) — twins; two children born from the same pregnancy
- 双方 (sōhō) — both parties, both sides; standard in negotiations, contracts, and disputes
- 双璧 (sōheki) — two people or things considered equal in excellence; "the two gems"
Body and Nature:
- 双眼 (sōgan) — both eyes
- 双肩 (sōken) — both shoulders; often figurative (e.g., 未来を双肩に担う = to bear the future on both shoulders)
- 双葉 (futaba) — twin seed leaves; a young sprout just breaking through the soil, associated with new beginnings
- 双翼 (sōyoku) — both wings; used literally and as a metaphor for two supporting forces
Tools and Objects:
- 双眼鏡 (sōgankyō) — binoculars; the compound literally means "both-eye lens"
- 一双 (issō) — a pair; the counter for matched sets such as folding screens (屏風), gloves, or shoes
- 双六 (sugoroku) — a traditional Japanese race board game, similar to Parcheesi or snakes and ladders
Expressions of Excellence:
- 無双 (musō) — peerless, unmatched; literally "without a pair" — so exceptional nothing compares to it. This word also gave its name to a famous video game franchise.
Academic and Specialized:
- 双曲線 (sōkyokusen) — hyperbola in mathematics; one of the conic sections
- 双数 (sōsū) — dual number; a grammatical category found in some languages to express exactly two of something
Example Sentences
彼女には双子の姉がいます。
Kanojo ni wa futago no ane ga imasu.
She has a twin older sister.
双方の意見をよく聞いてから判断しましょう。
Sōhō no iken o yoku kiite kara handan shimashō.
Let's listen carefully to both sides before making a judgment.
双眼鏡で遠くの山を眺めました。
Sōgankyō de tōku no yama o nagamemashita.
I gazed at the distant mountains through binoculars.
双葉が土から顔を出しているのを見て、春を感じました。
Futaba ga tsuchi kara kao o dashite iru no o mite, haru o kanjimashita.
Seeing a seedling push up through the soil, I felt spring had arrived.
あの二人は文壇の双璧と呼ばれています。
Ano futari wa bundan no sōheki to yobarete imasu.
Those two are called the twin pillars of the literary world.
この契約は双方が署名して初めて有効になります。
Kono keiyaku wa sōhō ga shomei shite hajimete yūkō ni narimasu.
This contract only becomes valid once both parties have signed it.
あの力士は無双の強さで横綱になった。
Ano rikishi wa musō no tsuyosa de yokozuna ni natta.
That sumo wrestler became a grand champion through sheer peerless strength.
双子の兄弟は見た目はそっくりでも、性格は全然違います。
Futago no kyōdai wa mitame wa sokkuri demo, seikaku wa zenzen chigaimasu.
The twin brothers look exactly alike, but their personalities are completely different.
国際会議では双方の利益を尊重することが大切です。
Kokusai kaigi de wa sōhō no rieki o sonchō suru koto ga taisetsu desu.
In international conferences, respecting the interests of both parties is essential.
Memory Tip
Picture 双 as two right hands (又 + 又) meeting in a handshake — two parties facing each other as equals. That image captures the character's meaning directly.
The word 双子 (futago, twins) makes a solid anchor: two children who arrive together, side by side. Look at the character itself — both halves identical, each one a mirror of the other. The structure shows the meaning.