[LoneMonad]

responder bids a 1 of a major w/4pieces and 6-9HCP
responder bids a 2 of a major w/5pieces and 16+HCP
responder bids a 2♣ w/10-15HCP
what structure guarantees finding a 3-5 or 4-4 fit in the majors after a 2♣ response?

[mtvesuvius]

Solution: Don't use this. It's pointless and extremely difficult to sort out after 4th hand pre-empt IMO.

To Answer your Question:

Over 2♣, 2♦ should ask... 2M is 4M, 2NT is No 4cM with No 5cm and 10-12, and 3m is No 4cM and 5m finally, 3M is 5M and 3NT is No 4cM with No 5cm and 13-15.

[rbforster]

Just pretend it's a regular 1♦ opener and bid the same as standard. Finds all the same major fits (although minor fits are a little worse since some sequences are more ambiguous).

[LoneMonad]

mtvesuvius, on Apr 13 2009, 09:08 AM, said:

Over 2♣, 2♦ should ask... 2M is 4M, 2NT is No 4cM with No 5cm and 10-12, and 3m is No 4cM and 5m finally, 3M is 5M and 3NT is No 4cM with No 5cm and 13-15.

but that leads to
3NT w/as few as 21HCP
or 4m w/as few as 21HCP

[TylerE]

Very easy...over 1♦, if you have a 4 card major you bid it. If you don't, you bid 1NT or 2♣/2NT/3NT depending on strength. The jump shifts are better used as weak.

[mtvesuvius]

LoneMonad, on Apr 13 2009, 12:52 PM, said:

mtvesuvius, on Apr 13 2009, 09:08 AM, said:

Over 2♣, 2♦ should ask... 2M is 4M, 2NT is No 4cM with No 5cm and 10-12, and 3m is No 4cM and 5m finally, 3M is 5M and 3NT is No 4cM with No 5cm and 13-15.

but that leads to
3NT w/as few as 21HCP
or 4m w/as few as 21HCP

That's why you shouldn't use this.

Just treat it like a standard 1♦ opener, and you will be fine.