Meaning
A secret advantage, plan, or resource you keep hidden until it’s useful, especially in competition or negotiation.
イディオム
ace up your sleeve
切り札や隠し玉のように、いざという時のために秘密にしている有利な手・策・情報があること。
competitioncommonintermediate
Origin
From card games and gambling: a player could cheat by hiding an ace in their sleeve and producing it later, so it became a metaphor for a concealed advantage.
Examples
She didn’t mention it in the meeting, but she had an ace up her sleeve: a signed contract from their biggest client.
彼女は会議では口にしなかったが、切り札を隠し持っていた――最大の取引先からの署名済み契約書だ。
I thought we were out of options until Raj revealed the ace up his sleeve—a backup server already configured.
もう手がないと思ったところで、ラージが切り札を見せた――すでに設定済みの予備サーバーだった。
Keep an ace up your sleeve in negotiations, so you’re not forced to accept the first offer.
交渉では切り札を一つ隠し持っておくと、最初の提案を受け入れざるを得なくならない。
The team looked nervous, but the coach had an ace up his sleeve and switched to a strategy they’d practiced in secret.
チームは不安そうだったが、コーチには切り札があり、秘密裏に練習していた戦略に切り替えた。
He acted surprised at the results, but it was clear he’d had an ace up his sleeve the whole time.
彼は結果に驚いたふりをしていたが、ずっと切り札を隠し持っていたのは明らかだった。
Notes (English)
Implies a hidden advantage or backup plan; can sound strategic or slightly sly. Used in competition, negotiations, or planning; acceptable in casual and business contexts. Avoid implying cheating unless intended.
Grammar & Usage Notes (English)
Usually used with “have/keep an ace up your sleeve.” Article is typically “an.” Can vary subject/tense (had/has/keeping). Often followed by “for” or “in case.”