It is possible to play a wide-ranging opening that covers more than one category, in which case the announcement should say so. Examples are: (a) “Intermediate to strong, forcing” (b) “Weak to Intermediate" For example, a 6-12 opening would be described as “Weak to intermediate”.
It is possible to have certain distributional constraints but this does not stop an opening being considered natural. E.g. a Precision 2§ opening is traditionally only made on a 5-cd suit when there is a 4-cd major, but also may be made with a longer Club suit and no major. A Precision 2§ is considered natural since no other suit is guaranteed and thus is announced as “Intermediate”.
On the other hand, some openings show another suit so are not natural. For example a Lucas 2ª shows another suit, so is not natural and is alerted, not announced.
Announcements - Others
An opening 1§ or 1¨ can be announced with “May be X” (X = 0, 1 or 2) if applicable. An opening 1♥ or 1ª can be announced with “May be 4” if applicable. No other statement, such as “better minor” or “Muiderberg” is permitted.
Basic alerting rules
Passes and bids Unless it is announceable, a pass or bid must be alerted if (a) it is not natural; or (b) it is natural but has an extra or potentially unexpected meaning.
Doubles The rules for alerting doubles are:
(a) Suit bids that show the suit bid Double of these bids is not alertable if for take-out; alertable otherwise
(b) Short, Nebulous, Prepared and Phoney minor openings Double of these bids is not alertable if for take-out; alertable otherwise
(c) No-trump bids Double of these bids is not alertable if for penalties; alertable otherwise
(d) Suit bids that do not show the suit bid Double of these bids is not alertable if showing the suit; alertable otherwise
Doubles are also alertable if they convey a potentially unexpected meaning in addition to take-out or penalties as defined above.
Redoubles The rules for alerting redoubles are: (a) Redoubles that are for business or show general strength, which partner is normally expected to pass if the next hand passes – not alertable. (b) Other redoubles (notably those partner is expected to take out) – alertable.
Calls above 3NT No calls are to be alerted except for: (a) Artificial suit bids on 1st round (opening bid and 3 subsequent calls) of the auction (b) Lead-directing passes (c) Doubles or redoubles that are lead-directing but ask for the lead of a suit other than the suit (re)doubled. This includes a Lightner double calling for a specific lead.
Improper use of alerts, questions and explanations Alerting, or querying an opponent's alert must never be solely for partner's benefit. Explanations of an alert are confined to descriptions of the hand alerted, and must not extend to cover behaviour of the alerter in response.
'Natural' Bids and passes
The following are considered 'natural' for alerting purposes
(a) A bid of a suit which shows that suit and does not show any other suit; the suit must be at least 3 cards long, but preference bids and raises may be on shorter suits. In the earlier rounds of bidding a natural suit bid usually shows at least 4 cards.
(b) A bid of no trumps which shows a preparedness to play in no trumps, and which conveys no unusual information about suit holdings; it must not be forcing unless a forcing auction has already been created.
(c) A pass that does not unexpectedly convey values or specify suit holdings.
Before the opening lead is faced, the declaring side must inform the opponents of any information about declarer's or dummy's hand that has been revealed by the auction but of which the defence may not be aware.
The defending side must do likewise but only after play of the hand is completed.