Bridge

1♥

bid
1♥
1♥
promises
  • 13+ HCP
  • 5+ hearts
  • hearts longer than spades
conditions
13+ HCP, H:5+, H>S
why

SAYC uses 5-card majors, so 1♥ promises a real 5-card heart suit. With equal majors, always open the higher (1♠) so you can rebid cheaply.

what happens next

Partner raises with 3+ hearts, bids 1♠ or 1NT without a fit, or makes a 2-level new-suit response with 10+.