Responder Splinter (11+ HCP):

• 1♣ - 3♦/3♥/3♠;

• 1♦ - 3♥/3♠/4♣;

• 1♥ - 3♠/4♣/4♦;

• 1♠ - 4♣/4♦/4♥.

After partner 1NT (HCP = 24 - min partner HCP):

• 3♥ - 4♠, 0-1♥;

• 3♠ - 4♥, 0-1♠.

If the bidder is the responder and the bid RHO is a double, the convention is off.