Major Trial bids


Trial bids  follow in opener's further rebids in all the following sequences:
  1. 1Ma - 2Ma - ?  (3+ card support for spades, 4 card support for Hearts)
  2. 1Ma - (LHO intervenes in a suit OR with a double) - 2Ma
  3. 1Ma - simple response - a 3rd suit - 2Ma   E.g (i) 1H-1S-2mi-2H  or (ii) 1Ma-2mi-2nd_suit_by_opener-2Ma
Note: In the 3rd type, responder is showing 3+ card support in (i) BUT usually only 3 card support in (ii).

The value range of the response is the SAME in all cases: (5-9HCP). Opener's rebid in a new suit is always aTrial bid. (A 2nd suit is not being shown).
In case 2 with an intervening double: the simple raise shows the same HCP range however responder may now make a distributional competitive raise to higher levels
In case 2 of an opponents simple suit overcall : a cue-bid rebid by opener is also a trial bid!
In both these sequences a trial bid rebid by opener in an unbid  suit, investigates essentially the difference between a somewhat pre-emptive initial raise AND a solid initial raise.