(ひとすじなわ)ではいかない

ひとすじなわではいかない
expression
not straightforward; not easy to deal with
1. not straightforward; not easy to deal with; tricky
Describes a person, situation, or problem that cannot be handled with ordinary methods and requires extra effort or skill.
あの(ひと)一筋縄(ひとすじなわ)ではいかない。
That person is not easy to deal with.
この問題(もんだい)一筋縄(ひとすじなわ)ではいかないぞ。
This problem isn't going to be straightforward.
国際(こくさい)交渉(こうしょう)一筋縄(ひとすじなわ)ではいかない相手(あいて)ばかりで、忍耐力(にんたいりょく)(もと)められる。
International negotiations are full of counterparts who aren't easy to deal with, and patience is required.

An idiomatic expression meaning that ordinary approaches won't work. Literally, 一筋縄(ひとすじなわ) means "a single rope" — the image is that a single rope (simple method) isn't enough to restrain or control someone or something.

USAGE:
Almost always used in the negative form ではいかない or じゃいかない. Can describe people (stubborn, clever, difficult), problems (complex), or situations (unpredictable).

COMMON PATTERNS:

  • 一筋縄(ひとすじなわ)ではいかない相手(あいて): a difficult opponent
  • 一筋縄(ひとすじなわ)ではいかない問題(もんだい): a tricky problem
  • 一筋縄(ひとすじなわ)ではいかない性格(せいかく): a difficult personality

SIMILAR EXPRESSIONS:

  • 手強(てごわ)い: tough, formidable — similar meaning but more concise
  • 一癖(ひとくせ)ある: to have a quirk; to be tricky — often about people
  • 簡単(かんたん)にはいかない: not easy — more straightforward phrasing