DOPI, ROPI and DEPO

You have agreed spades and bid 4NT, and the next player puts in 5♦. Partner's normal answers of 5♣ and 5♦ have gone. Opponents who expect you to bid a slam do this often, because a bid over your 4NT costs them little and can wreck the key card exchange. DOPI, ROPI and DEPO are short memory aids that restore the answers. They work the same way over Blackwood, over Roman Key Card Blackwood and over Gerber.

DOPI stands for Double 0, Pass 1. When an opponent overcalls your 4NT and the overcall is still below your slam, partner answers like this:

Holding nothing, partner doubles. The slam is off, and the opponents' sacrifice is probably going down a lot. Holding one, partner passes and leaves the decision to the captain, who can double for penalties, sign off, or bid the slam. Two or more and partner bids up the line, starting from the cheapest bid above the overcall.

Partnerships that play 1430 key cards often keep its groupings, so double shows the first step (one or four key cards) and pass the second (zero or three). Both versions work. What you must avoid is each partner playing a different one.

A double of 4NT takes no bidding room away, but it gives partner an extra call. ROPI, Redouble 0, Pass 1, puts that call to use. Redouble shows zero, pass shows one, and the normal steps continue from 5♣.

Some partnerships simply ignore the double and answer as if it had not happened, which works as long as both partners know it. ROPI gives the captain one more level of room, which matters most with clubs or diamonds as trumps.

When the opponents jump to the six level, there is no room left for steps. DEPO, Double Even, Pass Odd, keeps one bit of information. Partner doubles with an even number (zero, two or four) and passes with an odd number (one or three). The captain can usually tell which from the auction.

Where DOPI ends and DEPO begins is a partnership decision. Most pairs play DOPI when the overcall is at the five level and DEPO when it is at the six level. Some pairs switch to DEPO as soon as the overcall leaves no room for step bids below five of the trump suit.

Had South doubled to show no key cards, North would have known two were missing and passed the double, collecting a penalty from 5♥ instead. Without DOPI, South would have had no clear way to show one key card at all.

• Treating the double as natural. Under DOPI, partner's double of the overcall is an answer, not a penalty double. The captain decides whether to leave it in.
• Forgetting that pass is forcing. A DOPI or DEPO pass shows a holding and does not end the auction. The captain must act.
• Mixing up the 1430 groupings. Decide whether double means zero or the first 1430 step, and write it on your card.
• Using DOPI over a double. Over a double the agreement is ROPI, with redouble for zero and pass for one.
• Not agreeing where DEPO starts. Five level or six level, decide in advance.

What is DOPI in bridge?

DOPI is a way of answering Blackwood after an opponent overcalls 4NT. The name stands for Double 0, Pass 1. When an opponent overcalls your 4NT, partner doubles with no aces or key cards, passes with one, and bids the cheapest available suit with two, the next one with three.

What is ROPI?

Redouble 0, Pass 1. It is DOPI adapted for the case where an opponent doubles 4NT. Redouble shows zero, pass shows one, and the normal steps from 5♣ show two and three.

What does DEPO mean?

Double Even, Pass Odd. It is used when the opponents bid too high for step answers. Partner doubles with zero, two or four and passes with one or three.

Do DOPI and ROPI work with Roman Key Card Blackwood?

Yes. They count key cards instead of aces. Some partnerships also keep the 1430 groupings, with double showing one or four and pass showing zero or three.

Is a pass after DOPI forcing?

In practice, yes. The pass shows one ace or key card and hands the decision back to the 4NT bidder, who must double, sign off or bid the slam.