This is a disruptive method used to cause your opponents grieve. The suit opened is either a normal preempt in the suit bid, or a very weak preempt in another suit. Played only non-vulnerable, if the bid is passed out and the other suit is held, the opponents are only getting 50 per undertrick as a replacement for whatever contract they can make. These bids are usually disallowed in most forms of competition.
Only played not vulnerable:
a) decent weak two in diamonds, no four card major, 6-10, or
b) anything goes preempt in a major, 0-7, not good six card suit if 6-7.
a) decent weak two in hearts, 6-10, or
b) anything goes preempt in clubs, 0-5, at most one of top three honors in suit
a) decent weak two in spades, 6-10, or
b) anything goes preempt in diamonds, 0-5, at most one of top three honors in suit
Hand type b) is considered the "poor" hand type in the details below.
Responder is free to pass 2D, 2H, 2S openings with a hand that would pass weak two in that suit, since if poor hand type held, opponents likely cold for game. This is the reason openings only played non-vulnerable; at vulnerable the poor hand types are not held so 2D, 2H, or 2S are just standard weak twos.
a) Bid in a suit opener can have is pass or correct (p/c). If opener does not have suit bid by responder, responder will either make the cheapest bid in the suit held, or if a bid is available in between the cheapest bid in the suit held, it can be used to show the suit held and a maximum.
2S-Pass-3D(p/c)-Pass-3H=maximum 2S opening
2D-Pass-2H(p/c)-Pass-2S=0-7 & spades.
2D-Pass-2H(p/c)-Pass-3C=maximum 2D opening, a 3D rebid would show a minimum.
2H-Pass-3C(p/c)-Pass-3H=minimum 3H opening.
2H-Pass-3H(p/c)-Pass-3S=a maximum opening for a poor hand with clubs.
2D-Pass-4H(p/c)-Pass-Pass=0-7 & hearts.
b) Non-jump bids in new suits (suits opener cannot have) are natural, constructive but non-forcing. Opener only bids with the non-poor hand type but can pass if minimum & no fit as well.
2H-Pass-2S(NF)-Pass-3D=weak two in Hs, not minimum.
c) Jump bids in new suits opener cannot have are natural forcing if below game, to play if in game.
2H-Pass-4S= to play.
2S-Pass-4C= natural, forcing.
d) 2NT asks with at least mild game interest opposite poor hand type (otherwise use pass or correct).
With the ‘poor’ hand type, opener replies to 2NT:
With a normal weak two, opener replies:
2H-2NT-3S: weak two in hearts, maximum values, suit not headed by AQJ, AKJ, or AKQ (would have bid 3NT).
2D-2NT-3C-3S: pass with spades, or bid 3NT or 4H with hearts
2S-2NT-3D: diamonds and a good preempt for the poor hand type, about 4 to 5 HCP, with less opener would bid 3C
2H-2NT-3D: clubs and a good preempt for the poor hand type.