1. ace up one's sleeve, trump card, last resort

expressions (phrases, clauses, etc.) noun (common) (futsuumeishi) idiomatic expression

2. secret skills, secret, mystery

noun (common) (futsuumeishi) expressions (phrases, clauses, etc.) idiomatic expression

3. left hand

expressions (phrases, clauses, etc.) noun (common) (futsuumeishi) archaic