What does “die Fäden in der Hand halten” mean in German?

Die Fäden in der Hand halten is what you say about the person who secretly steers a situation, the way a puppeteer steers a marionette. Faden is “thread” or “string,” so the picture is literal. Germans use it for bosses, negotiators, or anyone running things from behind the scenes. A close variant is die Fäden ziehen, “to pull the strings.”

The Augsburger Puppenkiste, a marionette theatre in Augsburg known across Germany, shows where the image comes from. The puppeteers work from a high gantry with their backs to the audience, holding long threads that run to a Spielkreuz (the control cross), and every head turn or arm swing comes from a finger on a thread. Related phrases: am seidenen Faden hängen (“to hang by a thread”) and den roten Faden verlieren (“to lose the thread” of a story).