Ted Horning has written the daily syndicated column Canadian Bridge with Torstar Syndicate for over eighteen years-6600 columns and has been teaching bridge for more than thirty years. He has represented Canadian si different World Championship events.IMPs Dealer South. N/S Vul
A K Q 9 8 6
K Q 6
A K 5
There are two common conventios that deal with interference over ace-asking bids. One is DOPI – Double shows 0 aces, Pass shows 1 ace, and the nest step up (bid over opponents suit) shows two aces.
The second convention is DEPO. But in this case, Double shows an even number of aces, Pass shows an odd number of aces.
After studying the accompanying auction, consider the following questions:
a) Was North using DOPI or DEPO?
b) How many aces does North have?
c) What do you bid now?
You should bid 7As long as North was using DOPI, North showed two aces (Double = 0, Pass = 1, next step up the bidding ladder is 2 aces, another step up is 3 aces, etc.)
Was North using DOPI? Yes. Let me truncate the auction and present a diagram at the point where South asks for aces.
Interference above line (West bid 5) – North used DEPO.
DIVIDING LINE = 6 of our agreed suit (5)
Interference below line (West bids 5/5-North uses DOPI.
After South bids 4NT, if the interference by opponents is below 5 shows 2 aces. Had the interference by opponents been in spades (above the line), North would have used DEPO and would have doubled to show an even number of aces (0,2,4)
Bye the way, if an opponent with a sense of humor bids five or our agreed suit use DEPO
The complete deal: