BridgeHands

CAB - Control Asking Bid (Epsilon), an acronym associated with "Big Club" (Precision) and similar systems.  The convention, typically used in a game forcing auction subsequent to a Trump Asking Bid (TAB) or Ace Asking Bid (AAB), queries partner for the primary honors in a given suit.   Example:

1C - 1S;
2S -  3C;    2S is TAB, 3C is second step (Notrump is 1st), showing 1 top honor
3H -  ?       3H is CAB in Hearts, asking responder to identify Heart controls.

Control Asking Bid responses are (two methods are shown)
 

Step	Method 1 (fast shows)	Method 2 (slow shows)
1st	3+ low cards, no honors	First and second round of control, AK or AQ
2nd	Third round of control, Qxx or xx	First round of control, Axx or void
3rd	Second round of control, Kxx or x	Second round of control, Kxx or x
4th	First round of control, Axx or void	Third round of control, Qxx or xx
5th	First and second round of control, AK or AQ	3+ low cards, no honors

If asking partner rebids the suit as a further query, the responder makes a first or second step bid to shortage or honors values ("re-CAB), respectively.

"Compressed" Control Asking Bids occasionally are initiated at high levels, where using a 5 step response is inefficient.  When partner initiates a CAB at 5C or above, the following approach applies.

Compressed CABs:
 

Step	Method 1 (fast shows)	Method 2 (slow shows)
1st	No controls	First round of control, Axx or void
2nd	Second round of control, Kxx or x	Second round of control, Kxx or x
3rd	First round of control, Axx or void	No controls

Also see Precision systems, Alpha Cuebid , Beta Cuebid, Trump Asking Bid, Control Asking Bid, Suit Asking Bid, Delta Asking Bid and Precision/Big Club Books

Some Acol players play a CAB variation after opener's strong 2C bid.  Responses are:
 

2D	Less than 8 points and no Aces
2H	Holding the HA (possibly another Ace)
2S	Holding the SA, not the HA
2N	Holding 8+ points and no Aces
3C	Holding the CA, no major Aces (possibly the DA)