The requirement for a Michaels cuebid is a two-suited hand with at least 5 cards in each suit and typically 8-16 high-card points (HCP). Point count requirements vary, but it is commonly agreed that a Michaels cuebid is constructive and should be made on hands that hold the prospect of winning the auction. When made on very weak hands, the chances are the opponents will win the auction and will have been warned about the unbalanced holding of the Michaels bidder. Given that the Michaels cuebid is forcing, some partnerships apply no upper limit to its high card strength.
To use the convention, when the opponents make a one level opening, bid the same suit at the two level. There are two normal cases where this bid can be applied. Over an opponent's minor opening a cuebid shows both majors. For example, 1♣-2♣ shows hearts and spades. Over an opponent's major opening a cuebid shows the other major and a minor suit. For example, 1♠-2♠ shows hearts and either clubs or diamonds. Partner can make a 2NT relay bid to find out what the minor suit is.
Partnerships who have incorporated Michaels cuebid amongst their agreements, usually also play the unusual notrump convention.
As opposed to Ghestem, the 3♣ jump overcall is available as a natural bid. However, Ghestem is more precise in terms of uniquely defining the specific suits denoted. Another drawback compared to Ghestem is that following an opposing minor suit opening, the Michaels cuebid used in combination with the unusual notrump convention does not cater for a two-suiter in spades and the other minor. Hands like these can only be indicated by overcalling 1Spades and, if possible, later introducing the minor suit.
In the Netherlands, a particular modification is growing in popularity: over opponent's opening a cuebid shows a major and a minor unbid suit. The 2NT overcall is then used to show both majors (after a minor suit opening) or both minors (after a major suit opening). This approach allows all three two suiters in the three unbid suits to be indicated. Disadvantage compared to standard Michaels is that after an opposing minor suit opening one can not introduce a two suiter in the majors at two-level. Also, the cuebid invariably leaves one of both suits unspecified.
A variant often referred to as upper cuebid is popular in Germany. In this treatment a cuebid shows the highest unbid suit and another unspecified suit. Together with the unusual notrump convention to indicate the lowest of the two unbid suits, this approach allows all two suiters in the three unbid suits to be indicated. Disadvantage compared to Michaels is that after an opposing minor suit opening one can not in one single bid describe a two suiter in the majors.
Also, Michaels cuebid variants exist that remove any ambiguity on what is the second suit. An example is the hi-hi cuebid that over opponent's opening invariably shows the highest unbid suits. Together with the unusual notrump convention to indicate the lowest of the two unbid suits, this hi-hi cuebid allows two out of the three possible two suiters in the unbid suits to be specified in one single bid. A drawback of this method is that the hi-hi cuebid does not cater for two-suiters in the highest and lowest unbid suits.