Used after the partner opening 1♥/1♠ and no intervention:

• • 12+ HCP;

  • 4-card fit;

  • a game force.

Answers:

• • three in the new suit - singleton/void, 11+ HCP;

  • three of the agreed suit - no singleton/void, 16+ HCP;

  • 3NT - no singleton/void, 14-15 HCP;

  • four of the agreed suit - 11-13 HCP, no singleton/void.

After the intervention, the convention is off.