1.
instigation, manipulation, pulling strings behind the scenes
Secret manipulation or prompting by someone behind the scenes. Implies that a person's actions were actually directed or instigated by someone else. Almost always used with negative connotations.
Usage
Almost always carries a negative nuance of covert manipulation. The most common pattern is ～の差し金で (at someone's instigation). Originally, 差し金 referred to a carpenter's square or a device used in kabuki to manipulate stage props from offstage, hence the metaphorical meaning of hidden manipulation.