Source: 
Gazilli is more a “concept” rather than a welldefined convention: just as well as there are as many forms of Stayman (or Checkback, or whatever) as the number of bridge players, every pair plays a customized version of Gazzilli.
Gazzilli convention is a tool used for strong(ish) 1M opener hand when responder bids a 1-over-1.
1
: 1
or
1M:1NT (forcing or not).
In both of these sequences, 2
rebid by opener is EITHER a natural 2
rebid OR a 15 hand.
Over the 2
rebid, responder is required to rebid 2
with any 8 hand: in this case, opener will make a weak rebid if his 2
was natural, otherwise he”ll investigate or force to game, either by natural methods or using full relay systems.
If responder is very weak, he will skip the 2
rebid, 99% of the times giving a preference to opener”s major, OR by bidding his suit.
WARNING: there are different agreements of which bid use when responder is 2-suiter in misfit with minors (some people use 2NT), so there is no real “standard” for misfits hands, and each partnership will have to choose the most comfortable scheme.
The Gazzilli convention is very useful for hands too weak for a 3-level GF reverse but too strong for a minmum rebid at the 2 level: especially those 15-17 hands with a bad suit, that do not want to jump rebid at the 3 level. Using Gazzilli, one may as well give up the need to open 1NT with a 5 card major, since the rebid is not a problem.
Also, many pairs in Italy use the Gazzilli 2
for ALL strong 1M openings: that frees the jump to 3 of a suit and 2NT rebid for distributional hands, one common scheme is that:
– 3x rebid is a distributional reverse (5-5.5 hcp) with good suit(s) : 6 good single suiter or 55 if 2-suited;
– 2NT is distributional reverse with 6 M and a side 4 bagger (those hands when you don”t know whether to jump rebid your major, losing the side suit or to show a side suit, but showing it at the 2-level wd be an underbid and showing it at the 3 level would guarantee 55);
A “Power-reverse” (17 ) would rebid 2
, so these jumps are limited, they show only shape and concentrated values.
The Gazzilli 2
fits especially well in the Fantunes scheme (all 1-level bids forcing), when the 2C rebid is the start of relays for game/slam.
Finally, I want to emphasize that 2
Gazilli is more a “concept” rather than a welldefined convention: just as well as there are as many forms of Stayman (or Checkback, or whatever) as the number of bridge players, every pair plays a customized version of Gazzilli (relay versions, simple versions, etc etc).
The general principle, though, applies for all.
We will be publishing different Gazzilli convention versions during the next weeks…
