Jacoby 2 NT
2NT after partners 1H/S is showing 4 card trump support and game force.
The openers subsequent bids are:
-4H/S is showing a minimum opening
-3NT is showing a balanced hand with 18 - 19 points
-3H/S is showing long trump and extras
-3 of a new suit is natural and extras
 
Example 1:
A J 9 8 3 Q 7 5 2
5 3 A Q 7 6
Q 9 4 A 8 3
A Q 3 5 2
 
1S 2NT = Jacoby
4S = minimum pass
 
Example 2:
A K 9 8 7 Q J 3 2
A 5 K 3 2
4 2 A Q 3 2
A Q J 2 9 8
 
1S 2NT = Jacoby
3C = natural and extras 3D = cuebid
4NT = RKC Blackwood 5D = 1 ace
5H =queen of trump? 6H = yes, and king of hearts
6S pass