Source: Bocchi & Madala Big Bang Bridge

Read 1st Part

3NT Opening (nice opening in Hearts or Spades) 

3NT OPENING, ADVICE AND FURTHER DEVELOPMENT: In the first part (Read 1st Part),  I had developed some philosophy on the 3NT opening, now we are going to develop its continuations: the difference between 4club suitand 4club suitis: 4club suit is to play only game or I’m so strong that after knowing your suit I will ask you for keycards or a cue bid, while 4club suit would like to play slam only if you have a particular hand, (see below the developments).
Opening Answers
4club suit tell me your suit as in transfer (diamond for hearts, hearts for spades) can be a real slam invitation
4club suit mild slam invitation, tell me if you have a void or a particular hand
after your answer 4club suit  to play
after your answer 4club suit  to play
after your answer 4NT I understood your suit tell me your keycards and if you have the queen or not
Opening After 4club suitAnswer
3NT 4club suit
 4club suit/4club suit minimum
 4NT a major void (continuation: 5club suitasks)
 5club suit/5club suit a void (continuation: 5club suit/6club suit pass or correct)
 5club suit/5club suit 8 closed cards, or a 7-4 11 with very nice 7 cards and the 4 cards with at least an honour
An eventual 6club suit/7club suit is for pass or correct, if I have a good suit I ask for keycards and close after any answer.