The carpenter used a carpenter's square to check the right angle of the lumber.
instigation; manipulation; behind-the-scenes influence
Implies that someone is secretly pulling strings or orchestrating events. Often used in the phrase 差し金で動く (to act at someone's instigation).
His sudden resignation seems to have been at the president's instigation.
There must be someone's manipulation behind that incident.
prop wire (kabuki)
In kabuki, a thin metal wire used to manipulate prop animals like butterflies or birds on stage.
In kabuki, a prop butterfly is manipulated with a wire.
puppet control rod (bunraku)
In bunraku puppet theater, a rod used to control the arm of a puppet.
The bunraku puppeteer moves the puppet's arm with a control rod.
Standard kanji spelling for all senses.
Abbreviated spelling; less common but still used.
Rarely used kanji form.
差し金 first denotes an implement or rod inserted to measure, support, or manipulate something, including theatrical control rods and wires. The figurative sense developed from secretly directing a person or event as such a device directs a stage object.