South passed as dealer, and West opened this hand a Benjamin 2♣, alerted. I was called when the hand went down as dummy to determine whether it was permitted to open this hand with a strong artificial call. I told them that they should play the hand out while I looked into it, and that I'd be back with my decision.
Their convention card entry stated: "Benjamin, 21-22 or 8PT any suit".
The relevant regulation states that opening bids from 2♣ to 3♠ that don't promise an anchor suit or an unspecified suit of at least five cards must conform to the "extended rule of 25" as follows:
Quote
(a) any hand of at least 16 HCP, or
(b) any hand meeting the Rule of 25, or
(c) subject to proper disclosure, a hand that contains at least the normal high-card strength associated with a one-level opening and at least eight clear cut tricks.
Clear-cut tricks are defined as tricks expected to make opposite a void in partner’s hand with the second best suit break.
A K Q J x x x x x x x x x does count as 8 clear-cut tricks
A K Q x x x x x x x x x x does not
Hands conforming to the ‘Extended Rule of 25’ are described as ‘ER25’.
Further examples:
AKQxxxxx (7CCT), KQJxxxx (5), AQJ98xx (5), KQJTx (3), KQJTxxx (6), AKT9xxxxx (8), KJTxxx (2)
What would you say when you returned at the end of the hand?