Free, on Feb 13 2006, 11:17 AM, said:
There was a question asked what you open with a 4252. Well, in 1&2 seat you'll definetly open 1♦, but in 3rd seat you may open 1♠. I know someone who even opened 1♠ on QJ98-Ax-AKQJxx-x, planning to rebid 3NT. His partner supported ♠ however, so he just jumped to 6♠ which was doubled and just made. 
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Playing Acol(12-14 1NT, that is 11-13 with this good shape) you must, if in the 1NT range, be prepared to rebid you 5-card since a rebid of 1NT shows a stronger hand. But with a 4-card spades it is not a problem since you can pass reponder's 1NT (6-9 or some such, depending on partnership agreements).
Playing SAYC(15-17 i.e. 14-16 1NT), you must be prepared to rebid a new suit if you open one-of-a-suit with a hand in the 1NT range, since you are too strong to pass responder's 1NT (6-10).
With a 4225 or 4252 and 11-13 HCPs, playing Acol you can open either 1NT or 1m. SAYC-players should open 1NT with 4252 and 15-16 HCPs since otherwise you don't have a good rebid over partner's 1NT response.
With 2425 or 2452 and 11-13 HCPs, Acol-players should open 1NT if the minor suit is not strong enough to rebid.