A Michaels Cuebid is a conventional overcall in the same suit as an opponent's opening bid, derived by Michael Michaels of Miami Beach, Florida. It promises a two-suited hand, with at least five cards in each suit. Simply put, if the opening bid by the opponent is in a Minor suit, 1♣ or 1♦, your respective bid of 2♣ or 2♦ shows 5-5 in the Majors, Hearts and Spades. A Michaels Cuebid of opponent's opening of 1♥ or 1♠ shows the other Major and an unspecified Minor. Partner can bid 2NT following your bid of 2♥ or 2♠, to request you to bid your Minor.
To illustrate the effectiveness of Michaels Cuebids, I would like to start with the first of two successive deals from a recent tournament, which involved use of the convention.
East's opening bid of 1♠, saw a Michaels Cuebid of 2♠ from my partner in the South seat, showing at least 5 cards in both Hearts and one of the Minors. West passed and I was now forced to respond to Partner's cue bid. I had no tolerance for hearts but was quite happy for us to play in either Minor, so I bid 2NT. East was not letting us have it too easy and bid 3♠. Non-plussed, my partner bid 4♣, showing both her Minor suit and additional values. I had little hesitation raising her to the Club game. She ruffed the opening Spade lead, drew trumps in two rounds. Next came the A♥ from her hand followed by a small Heart which she ruffed on the table, felling East's K♥. The next trick went to East's ♦A but, on regaining the lead in the closed hand, partner was able to successfully effect a ruffing finesse against the Q♥ in the West hand to land the contract with an overtrick. We scored a second top - one pair having bid and made the Club slam while the other N/S pairs were restricted to 6 or 7 tricks in 3NT.
Michaels works well in conjunction with the Unusual 2NT, which is another convention for two-suited overcalls. For example, a bid of 2NT over opponent's opening of 1♥ or 1♠ shows both Minors. There is also Ghestem, a more complex overcall structure for showing any type of two-suited hand but whatever conventions you chose, be aware that if you do not win the contact, the information you give about your distribution may be of advantage to the opponents. This brings us to the second hand:
My partner, sitting South, opened the bidding with 1♦. West bid 2♦ for the Majors, I bid 2♠, showing 11 or more points, good support in Diamonds and a control in Spades suggesting the possibility of a game in No Trumps if partner's hand was suitable. Perhaps dazzled by the 9's and deuces in his hand, East put in a cheeky non-vulnerable bid of 4♥, putting paid to any hopes we had of landing an easy 3NT contract. Not to be outdone by the opponents' shenanigans, partner now bid 5♣ showing her second 5-suiter and, admittedly, better quality suits in the Minors than she actually had. Reckoning that 3 down doubled non-vulnerable was a good sacrifice against our vulnerable game, West rightly continued with 5♥ and I was in a quandary. After some thought, I eschewed the double and bid an ambitious 6♣, passed all round.
Partner won East's opening Spade with the ♠K in her hand and saw that she would be able to discard her Heart loser on dummy's ♠A so the Major suits posed no problem. However, from West's 2♦ Michaels Cuebid, she knew that West had at most 3 cards in the Minors and so she had to be wary of one of the Minor suits breaking badly. Forearmed with the possibility of East having all four missing trumps, she played brilliantly to bring home the slam contract. Even with all four hands exposed it's not easy to see how she accomplished this.