upper hand

Possibly an allusion to card games such as poker in which hands are the sets of cards held by players.

the upper hand (usually uncountable, plural upper hands)

1. (idiomatic) Advantage or control.
   • 1855, Washington Irving, "Guests from Gibbet Island":

     There was no refusing him, for he had got the complete upper hand of the community, and the peaceful burghers all stood in awe of him.

   • 1883, Robert Louis Stevenson, chapter 23, in Treasure Island:

     [C]uriosity began to get the upper hand, and I determined I should have one look through the cabin window.

   • 1911, Joseph Conrad, chapter 1, in Under Western Eyes:

     There it was Razumov who had the upper hand, in a composed sense of his own superiority.

   • 2003, Christine Gorman, "Playing Chicken With Our Antibiotics," Time, 14 Feb.:

     And because they live everywhere and reproduce quickly, bacteria have the upper hand.

• hold the cards
• whip hand