Translation guide
The English word 'balls' can refer to spherical objects, testicles (slang), or courage/bravery (slang). This guide covers natural Japanese expressions for each meaning, with emphasis on common usage and register.
Referring to round objects used in sports, games, or as general items.
The most common word for 'ball' in sports and play. A loanword from English, used for baseballs, soccer balls, tennis balls, etc.
ボールを投げてください。
Please throw the ball.
彼はボールを蹴った。
He kicked the ball.
A native Japanese word for 'ball' or 'sphere'. Often used in compounds or for small round objects. Can sound slightly more formal or technical than ボール.
水晶の球
a crystal ball
Same reading as 球, but this kanji is used for jewels, beads, or small round objects like pachinko balls. Not typically used for sports balls.
ビー玉
marbles (glass balls)
Referring to male reproductive organs in a vulgar or informal way.
The most common slang term for testicles. Literally 'gold balls'. Crude but widely understood.
金玉が痛い。
My balls hurt.
The medical/anatomical term for testicles. Used in formal or clinical contexts.
Slang abbreviation of 金玉, often used in casual speech. Can be written in katakana for emphasis.
タマを蹴られた。
I got kicked in the balls.
Expressing that someone has guts, nerve, or audacity.
Japanese does not use 'balls' metaphorically for courage. Instead, use 度胸 (courage, nerve) or 勇気 (bravery). 度胸 implies boldness or guts; 勇気 is more general courage.
彼は度胸がある。
He has balls (guts).
そんなことを言うなんて、勇気があるね。
You've got balls to say that.
An idiomatic phrase meaning 'to have nerves of steel' or 'to be unshakable'. Conveys a similar sense of boldness.
あいつは肝が据わっている。
That guy has balls of steel.
Means 'to have guts/willpower'. Often used in contexts of perseverance rather than audacity, but can overlap.
彼は根性があるから、最後までやり遂げた。
He has balls, so he saw it through to the end.
English uses 'balls' as slang for bravery, but Japanese does not. Using 金玉 in this context will be confusing or offensive. Use 度胸 or 勇気 instead.
ボール is the default for sports balls. 球 (たま) is used in compounds or for non-sport spherical objects. 玉 (たま) is for small round items like beads or jewels.
睾丸の検査を受けた。
I had a testicular exam.