up one's sleeve
have
a
trick
, some more tricks, etc.
up
your
sleeve
to have an idea, some plans, etc. that you keep ready to use if it becomes necessary
I have a few tricks up my sleeve.
e.g.
/fe3hdialogue/アンナ外伝 秘密の商人 The Secret Merchant#62809693bdb0e50000c36b8d
/fe3hdialogue/打ち砕かれた策 Disintegrating Plans#5e623750bdb0e50000d92794
/fe3hdialogue/Edelgard×Constance#61303e77bdb0e50000d22183
have
/
keep
something
up
your
sleeve
to keep a plan or an idea secret until you need to use it
Actually I do have a few ideas up my sleeve.
e.g.
/fe3hdialogue/挑発・金鹿の学級 The Golden Deer Rise#5e520721bdb0e500001ececc
/fe3hdialogue/水上都市 The Aquatic Capital#6378f418bdb0e50000b27e32
/fe3hdialogue/それぞれの覚悟 Resolve#62921868bdb0e50000b24ba6
/fe3hdialogue/Ignatz×Flayn Support Conversations#6178c14fbdb0e5000074335e