DOPI (and ROPI)
(Acronym for Double - 0, Pass - 1) [after RKCB it has altered to: Double = 0-3, Pass = 1-4, next step = 2 without the trump Queen, second step = 2 with the trump Queen].
It is used when an opponent overalls after partner biids 4NT (or 4♣) asking for Aces (but only when the overcall is below 5 of the trump suit):
Responses to 4NT (RCKB) when opponent interferes:
- Double= 0 or 3
- Pass= 1 or 4
- Next step = 2 without the trump Queen
- Second step = 2 with the trump Queen
E. g. after 4NT (asking Aces in spades)-Ovecall 5♣: Double = 0 or 3, Pass = 1 or 4, 5♦ = 2 without ♠Q, 5♥ = 2 with ♠Q.
Similarly, when opponet doubles 4NT, ROPI is used (Redouble = 0-3 and Pass = 1-4.
A variation of the convention also exists, with the concepts of double and pass reversed (PODI: Acronym for Pass - 0, Double - 1)
DEPO
If the interference is above 5 of the trump suit (e. g. after 4NT (asking Aces in hearts)-Overcall 5♠), then with 2 Aces the auction will rise to a dangerously high level. In this case DEPO (Double Even, Pass Odd) is used, which is less clear than DOPI but at least the bidding remains at safe levels.
Responses to 4NT (RCKB) when opponent interferes:
- Double = Even number of Aces (0, 2 or 4)
- Pass = Odd number of Aces (1, 3 or 5)
E. g. after 4NT (asking Aces in hearts)-Overcall 6♦: Double = Even Aces (0, 2 or 4), Pass= Odd Aces (1, 3 or 5).
