Unusual vs. unusual

Read main articles: Contract bridge, Bidding system, Bridge convention and Glossary of contract bridge terms

Unusual vs. unusual is a competitive bidding convention used in contract bridge by the opening side after an opponent has made an overcall showing two suits (e.g., a Michaels cuebid or an unusual notrump overcall.

Countermeasures

The opening side may compete against the opponent's intervention; actions depend upon whether one or both of the opponent's suits are specified:

Both suits are specified

• A bid in partner’s suit or a new nonadverse suit is competitive without showing game interest.
• A cuebid of the opponents’ lower ranking suit shows an invitational limit raise of partner’s suit with a likely 5-card side suit in the other nonadverse suit.
• A cuebid of the opponents’ higher ranking suit shows a game forcing raise with a likely 5-card side suit in the other nonadverse suit.
• A double shows the ability to penalize at least one of the opponent’s two specified suits. Any subsequent double by the partnership is for penalty.

Only one suit is specified

• A bid in partner’s suit or a new nonadverse suit is competitive without showing game interest.
• A cuebid of the opponents’ known suit shows a raise of partner’s suit. The raise is invitational limit raise or stronger. The cue bid raise implies a 5-card side suit (probably, not the overcaller’s unspecified second suit).
• A double shows the ability to penalize at least one of the opponent’s implied suits. Any subsequent double by the partnership is for penalty.

Additional information

Typically, raises show either four-card or longer trump support or three-card support with a splinter in a known, adverse suit. Since the overcaller with the two-suited hand probably has a short holding in the opening side's trump suit, one expects the adversely held trumps to break unevenly. Thus, the opening side should have either nine or more trumps or good ruffing values in the hand with short trumps.

The unusual vs. unusual (or, unusual over unusual) convention has many variants and only one is presented in the foregoing. Thus, a partnership agreement to play the convention requires detailed review of the initial responses and their continuations.