All openings from 2
up systemically disturb the auction, and all continuations are systemic.
The suit bids are all pre-emptive in nature, and of one of three types – sound, unsound or positive – both as openings and as overcalls. So an opening 2 is a classic weak two, and in response new suits are forcing, 2NT is a forcing fit bid agreeing the suit and direct raises are (semi-) pre-emptive.
An opening 2NT is a systemic two-suiter, showing opening strength with at least five in both minors. With 5422, you should open 1NT; with six-four you should open two of the longer minor; with 5431, you can open two of the longer minor in third hand, but should pass in first or second hand.
Although opener will have a second chance to bid, it is important not to open 2NT with hands strong enough to open 1
, as responder will be forced to bid 3 or 3
on a very wide range of hands, from nothing to near game values. Continuations were discussed earlier under 2NT.
High no-trump bids are as common as flying pigs. Systemically, 3NT, 6NT and 7NT are to play, 4NT is Blackwood and 5NT is 'pick a slam', although it is difficult to think of any suitable hands that could not be bid by some less extreme means.