DOPI (Double = 0, Pass = 1) and ROPI (Redouble = 0, Pass = 1) are defensive conventions used when the opponents interfere over your Blackwood or RKCB ask. They allow you to still show your keycard count despite the interference.

The Problem

Partner bids 4NT (Blackwood), and RHO interferes with 5♣. Now what?

• You can’t make your normal response
• Double might be penalty
• Pass is ambiguous
• You lose the ability to show keycards accurately

DOPI: After an Opponent’s Bid

Double = 0 keycards (or 3 in RKCB) Pass = 1 keycard (or 4 in RKCB)

Next steps up show 2, then 2 with queen, etc.

Example:

Auction	You hold	Your bid
4NT – (5♣) – ?	0 keycards	Double
4NT – (5♣) – ?	1 keycard	Pass
4NT – (5♣) – ?	2, no queen	5♦
4NT – (5♣) – ?	2 with queen	5♥

ROPI: After an Opponent’s Double

When RHO doubles your Blackwood ask, you have an extra call available (Redouble):

Redouble = 0 keycards (or 3) Pass = 1 keycard (or 4)

Example:

Auction	You hold	Your bid
4NT – (X) – ?	0 keycards	Redouble
4NT – (X) – ?	1 keycard	Pass
4NT – (X) – ?	2, no queen	5♣
4NT – (X) – ?	2 with queen	5♦

Memory Aid: “DOPe-y ROPER”

• DOPI = Double shows 0 (the “DOPe” has nothing!)
• ROPI = Redouble shows 0

In both cases, Pass shows 1.

Variations: DEPO and REPO

Some partnerships invert the meanings:

DEPO: Double = Even (0 or 2), Pass = Odd (1 or 3) REPO: Redouble = Even, Pass = Odd

This can be useful in RKCB where you might want to distinguish between even and odd keycards. However, DOPI/ROPI is more common and simpler.

Extended DOPI (EDO)

Some partnerships extend DOPI when interference is higher:

After 4NT – (5♠):

• Double = 0
• Pass = 1
• 5NT = 2, no queen
• 6♣ = 2 with queen

The principle remains the same: Double and Pass are the two cheapest “responses,” then bids continue up the line.

When DOPI/ROPI Applies

The convention activates when:

1. Partner has bid 4NT (or your Minorwood/Kickback bid)
2. RHO bids or doubles
3. You have room to respond below the trump suit

If interference pushes you beyond your trump suit, you’re in judgment territory—bid slam with enough keycards, pass/double otherwise.

Why Play DOPI/ROPI?

Without this convention, opponents can disrupt your slam auction badly by interfering over Blackwood. DOPI/ROPI lets you:

• Show your keycard count despite interference
• Turn their bid/double into extra information
• Continue accurate slam exploration

It’s part of every serious partnership’s defensive toolkit.

See also: Roman Keycard Blackwood, Blackwood, Exclusion Blackwood