Cubids
Cuebids are used when a trump suit is agreed to find out if the partnership has enough controls to bid and make a slam. In Topbridge we are using "Italian Cuebids", meaning that we are showing both 1st and 2nd round controls. 1st round control = ace or void, 2nd round control = king or singleton. A cuebid in partners suit is showing ace or king.
 
Example 1:
A Q J 5 3 K 10 9 8
3 A 10 8 2
K Q 10 9 3 4 2
10 2 A K 3
 
1S 2NT = Jacoby 2NT
3D 3H = cuebid
4D = cuebid 4NT = RKC Blackwood
5D = 1 ace 5H = asking for queen of trump
6D = trump queen and king of diamonds 6S
pass  
 
Example 2:
A 7 K 3
K Q 8 5 3 2 A J 10 9 4
K J 7 A 8
9 4 Q J 3 2
 
1H 2NT = Jacoby 2NT
3H =6 hearts, not minimum 3S = cuebid
4D = cuebid 4H = realizing that the partnership is missing a club stopper
pass  
 
Example 3:
A 7 2 K 3
K Q 3 A J 10 9 4
Q J 7 3 2 A 8
A 9 Q J 3 2
 
1NT = 15-17 2D = Jacoby transfer
2H 3C = game force with at least 5H and 4C
3H = 3H and not minimum 3S = cuebid
4C = cuebid 3D = cuebid
4NT = RKC Blackwood 5H = 2 aces, denying queen of trump
5NT = grand slam try 6H = no extras
pass