Jacoby
Above 2 NT, any bid is a Jacoby transfer. An impossible Jacoby (for the opponent's suit), is a Stayman : that's a forcing bid requiring at least 8 HCP and a 4 card major...
- 1 SA - 2 ♦ (or 2 ♥ or 2 ♠ ) - 2 SA : 2 SA Jacoby for ♣ (6 cards)
- 1 SA - 2 ♥ (or 2 ♠) - 3 ♣ : 3 ♣ Jacoby for ♦ (6 cards)
- 1 SA - 2 ♣ ( or 2 ♦ or 2 ♠) - 3 ♦ : 3 ♦ Jacoby for ♥
- 1 SA - 2 ♣ ( or 2 ♦ or 2 ♥) - 3 ♥ : 3 ♥ Jacoby for ♠
- 1 SA - 2 ♥ - 3 ♦ : 3 ♦ looks like an impossible Jacoby, the responder can't be willing to play 3 ♥ : this is a Stayman for ♠ : game forcing. If the responder didn't want to go to game, he would have doubled .