Rule of Twenty
This is more of a quibble about Book One than any intent for a discussion.
Whenever I teach Rule of Twenty I always stress that the notes in Book One are slightly misleading. I say that you can or could consider opening on the rule, but you must be prepared for ANY response by your partner. Don't open under the rule if you would have to rebid a very poor suit, eg if you held:
K J 7 4
Q 8 5 4 3
What would you do, having opened 1C if Partner responds 1S or worse still - 1NT?
Change this to:
Q J 5 4 3
K J 7 4
This is worth opening as you have an easy rebid, whatever your partner does.
The examples and text at the bottom of p31 are fine (especially as all the hands have Aces and Kings!) but the need for a valid rebid should be stressed. I'm probably just fretting over the use of the word "worth" in the text - implying actually doing it as long as the rule is satisfied. I don't think it's that simple.
On the same subject, at the Teachers Conference, I bought a copy of the new EBED flippers and note that on the page on "Opening 1 of a Suit" it implies only using the Rule of Twenty with 11 HCPs. Is this a deliberate change of intent? Will the new Book One drop using it with 10 HCPs?