Posted 2012-May-23, 17:14
OP has asked: " In this situation...is a single D a 2nd round control bid? (Partner has shown all keycards) " .
The FIRST K-ask requires the cheapest bid K reply ( NOT a singleton ) .
The SECOND K - ask CAN show a singleton since the reply structure can show this:
For example ( ♠ are trump ):
4NT ( RKC ) - 5H ( 2 - ♠Q )
5NT ( K-ask ) - 6C ( ♣ K )
6D ( 2nd K - ask ) - ??
........................ 6S = NO ♦ K or singleton
........................ 7S = ♦ - singleton
........................6NT = ♦ K but no ♦ Q
........................ 7D = ♦ K Q
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
For OP's given hand, if you used 5NT as the FIRST K-ask, the reply would have been 6D = ♦ K, denying the ♣ K .... and 7NT could have been bid with confidence .
In my RKC stucture, which is more standard, 6C ( over the 5H reply, by-passing the K-ask bid ) would have been a 3rd-Rnd-Ctrl-ask in ♣.
Don Stenmark
TWOferBRIDGE
"imo by far in bridge the least understood concept is how to bid over a jump-shift
( 1M-1NT!-3m-?? )." ....Justin Lall
" Did someone mention relays? " .... Zelandakh
K-Rex to Mikeh : " Sometimes you drive me nuts " .