When In Rome

RHO	You	LHO	Partner
2 ♦	?

11-15 HCP, 4441 or 4450 pattern

Your opponent's opening bid is known as Mini-Roman 2 ♦. The original Roman 2 ♦ opening bid showed 17-21 HCP, hence the "mini" appellation here. Some partnerships make this call with any three-suited hand. Other partnerships require a four-card spade suit, and a few even require opener to be 4-4 in the major suits under certain conditions.

With game interest, responder typically bids 2 NT asking for more information; usually "where is the singleton?" Otherwise, the partnership bids four-card suits up the line until a suitable fit is located.

Now what?

The usual defense against a Mini-Roman 2 ♦ opening (and Precision 2 ♦, very similar) is as follows:

• Double shows a strong hand (at least 15+), usually balanced, with some offensive potential but primarily defensive values. Any subsequent doubles are for penalty. This Double must be Alerted ("penalty oriented, 15+"). Partner is allowed to bid holding a good suit of her own; all of partner's bids are natural and nonforcing.
• Suit overcalls are natural and show a good suit, knowing that your right-hand opponent might have four of your trumps. The overcall is nonforcing, the same as any other overcall.
• 2 NT is to play, invitational to 3 NT. This hand is stronger than a Double (perhaps 18+) with values that are more offensively oriented; for example, a long suit as a source of tricks. 
• Otherwise, Pass is a good choice.

Other than in direct seat, all subsequent actions are natural. Doubles of artificial bids show the bid suit; other doubles are for penalty. Because opener has four-card support for three suits, there is no point in takeout doubles. Similarly, aggressive balancing in these auctions is usually a losing proposition.

Opening leads after a Mini-Roman 2 ♦ auction: The standard advice is lead trump. Declarer will usually be looking to ruff in her short suit. The opponents might have scrambled to land in a 4-3 fit. In either case, your job is to neutralize the trump suit as much as possible. If you have some other compelling lead, go ahead and make it; but your default lead will be trumps.

-- Ray 

Better Bridge in 5 Minutes. Guaranteed! (or the next one is free)