[Trick13]

Currently our multi 2♦ promises 6-cards in a major, and our 2♥/♠ opener shows exactly 5.

I'm considering the impact of including the 5-card suits in the multi 2♦. This would free up 2♥/♠ for other purposes, but would restrict responder's ability to raise preemptively which seems bad.

Has anyone experience with this?

[helene_t]

I have played it a bit and I think it sucks. It becomes too much of a gamble when responder has a weakish hand with shortness in a major or an invitational hand with a doubleton in a major.

It might work if you adopted some high tech response structure that allows responder to show various hands with length in a major. Because the main issue is to land on your feet when you have a fit in another suit, especially the other major.

[Free]

Playing it as 5 or 6 is a really bad idea. For starters, a multi doesn't allow you to preempt as much as you'd want to (because you need a double fit) and if you allow 5 card suits you'll rarely be able to raise to 3-level. Also your constructive auctions will be poor because you don't have enough space to show min/max, 5/6 card suit, ♥/♠ and maybe even some features about the hand. And last but not least, landing on your feet will also become problematic. Now with a singleton you can just bid a Major as P/C, but when opener can have a 5 card suit you might end up in a 5-1 fit while a much better fit in a side suit is available. A weak two being 5 or 6 is already difficult to play, a multi makes it much worse!

Playing it as exactly 5 is playable but not advisable imo (unless with a destructive character) because opener can have more hands while you still have the same bidding space available.