Blackwood or Quantative 4NT?
If a support fit has already been established, 4NT is always Blackwood. However, if a fit hasn't yet been established, sometimes you need to stop and think!
- Certain bids specifically imply a fit : Splinter, a jump fit and especially a Texas rectification jump bid, so when 4NT is bid this is Blackwood..
- After a 1C0 opening bid and a fit hasn't yet been established and your P bids 4NT ... this is Blackwood. Your P is fitted and doesn't want to give the Opps bidding space to find a "sack" contract.
- In certain bidding sequences, your P doesn't have the bidding space for a forcing Slam bid, when he bids 4NT this is Blackwood and implies a support fit.