Bridge is an open game, and partnerships are not allowed to have secret understandings. Hence we are obliged to alert certain bids which may not have an obvious meaning to the opposition. Players are required to give a full explanation of the meaning not just quote the name of a convention. Players may choose to deviate from the agreed points range provided partner is not aware. Alerts apply to Club bridge, playing duplicate pairs or teams. Playing Rubber bridge: you need not alert or announce any bids.
Bids which are alertable are:
1.Conventional bids in a suit where the suit bid may be less than 3 cards or even none at all
2. Conventional bids in no-trumps where the bid indicates certain suit holdings or asking for specific information
3. Bids in a suit where the suit has at least 4 cards, but shows a second suit
4. Any bid that has a much different points holding than would be expected or is forcing where the expectation is different (i.e. a forcing 1NT response)
5. Doubles that are the reverse of what may be expected, or doubles of artificial bids to direct a lead.
You do not alert:
1. Opening bids at the two level showing the suit- these are announced
2. Transfers over 1NT these are announced, likewise Stayman with simple responses.(e.g. provided there are no responses to show both majors, Stayman is then alerted) .
3. Trial bids after suit agreement where the trial suit is at least 3 cards
4. New suit bids at the 4 level after 3 bids have already been made (e.g. cue bids)
5. Doubles of weak twos , weak three bids if they are for take-out
If a bid is not alerted you should assume it is natural and not ask the meaning of the bid.
Examples of when you must alert
1. An opening bid of 2 / that is for a very strong hand or 8 playing tricks in an undisclosed suit. Alert also any relay or negative response. If the opening bid 2 bid always shows a suit of at least 5 cards, it can be announced as “strong”
2.An opening bid of 1 (Precision, strong club, or showing no 5 card suit unless it is s)
Two card openings in minor suits are announced not alerted in a 5 card major system
3. Conventions such as: 4th suit forcing, directional asking bids, unassuming cue bids, Jacoby 2NT response to a major suit opening, CRO or the unusual 2NT.
4. Bids like Lucas two openings in a major because they show that major and a lower 5 card suit
5. Inverted minor raises where a single raise in the minor is forcing.
6.Bergen raises in majors (where a new suit response at the 3 level gives a specific points count, and a raise in the suit at the 3 level is very weak.)
7. A double of 1NT that is for take-out not penalties, or a double of a 1 level suit contract that that is for penalties not take-out.
8. Short suit trial bids
9. Splinter bids
10 A multi -two diamond opening bid that has three possible hand types (strong and weak)
11. ASTRO, Landy, Cappalletti and similar defences to opponents 1NT opening bid. Natural bids of two of a major in these conventions showing at least a 5 card suit need not be alerted.
12. A Gerber bid of 4 asking for aces, if it is the second or third bid in the auction