In the game of bridge, Ghestem is a conventional overcall structure, using 2NT, 3♣, and the (non-jump) cuebid over an opposing opening at the one level to denote two-suited hands in two of the remaining three suits.
Point counts vary, but it is commonly agreed that a Ghestem bid is constructive and should be made on hands that hold the prospect of winning the auction.
This second disadvantage can be overcome by changing the order of the two suits shown by each bid;[1] methods include RCO, inverted Ghestem (Questem) and Specific Michaels (SpoDo), although the similar and quite popular CRO fails to achieve this.
Given that over a 1♦ opening the majors have to be introduced at three level, many partnerships who play Michaels have agreed that over an opposing 1♦ opening a modified structure applies that retains the availability of a natural 3♣ overcall: To overcome the problem of having to introduce the majors at the three level over an opposing 1♣, and in order to retain the natural (1♣)-2♣ overcall (indicating a good 5+ card suit), some partnerships also apply a modified structure over 1♣: A modified structure that allows the partnership to introduce the majors at the two-level after both minor suit openings is attributed to Garozzo:[2] Notice that in this variation of Ghestem following a 1♣ opening, one retains the option to make a natural 2♣ overcall.
As (1♦) - 3♣ is non-forcing, partnerships playing Ghestem à la Garozzo can use (1♦) - 3♦ to introduce very strong black two-suiters, or begin with a simple 1♠ overcall.