[awm]

I was examining some unusual preempt styles today and computed some interesting statistics. Dunno if this means anything...

(1) Standard weak 2♥, showing 6♥ and 4-10 hcp, no 5-card side suits. Frequency about 1.88% of hands. Hearts are the best fit about 79.4% of the time.
(2) "Five-plus" weak 2♥, showing 5-6♥ and 4-10 hcp, not 5332 shape. Frequency about 7.59% of hands. Hearts are the best fit about 66.2% of the time.
(3) Flat 2♥, showing 5♥-(332) and 5-11 hcp. Frequency about 2.09% of hands. Responder can guess the best fit about 98.4% of the time.
(4) Flattish 2♥, showing 5-6♥ no singleton or void and 5-11 hcp. Frequency about 4.30% of hands. Responder guesses the best fit about 91.8% of the time.
(5) Ekren-style 2♥, showing 4+♥ and 4+♠ and 7-11 hcp, not 4♦. Frequency about 4.36% of hands. Responder guesses the best fit about 76.8% of the time.
(6) Hyper-active Ekren style 2♥, showing 4+♥ and 3+♠ and 7-11 hcp, not 4♦. Frequency about 8.50% of hands. Responder guesses the best fit about 70.3% of the time.

Some observations: the Flat 2♥ is actually more frequent than the traditional weak two, and virtually guarantees that we find our best fit. Note that neither of these hand types is one that standard systems would open at the one level. The Flattish 2♥ is roughly as frequent as a limited Ekren, and has a much higher chance of enabling responder to reach the best fit. The "five-plus" style weak two actually has a pretty decent shot at landing in the wrong suit, since the heart bid promises only five and partner knows little about the remaining shape; it might be better to play the hyper-active ekren style which is substantially more frequent, has a slightly tighter point range (the way I have defined it anyway) and has a bit better chance of reaching the best strain.

Note that I've assumed a "weak 2♥" plays in hearts and that an "ekren 2♥" plays in a major; in either case it might be possible to get out in a different strain on a less-than-inv shapely responder hand depending on your methods, but these types would seem to require a six-card suit which won't be that high frequency. One could obviously play different point ranges; I've given the Ekren-style bids a narrower range because opener's large range of patterns and lack of a long suit makes it more dangerous to "invite" on a lot of sequences (perhaps those with experience playing those methods can comment on this). In all cases I wanted the maximum point value to be "just short of a normal one-level opening" which is perhaps 12 points on a flat hand or 11 with a bit of shape.

[bluecalm]

Very interesting. If anything now I know how often opener has 5carder if he opens every 5 and 6 card suit (much more often)

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Flat 2♥

First time I hear about this style. Seems fun.

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it might be better to play the hyper-active ekren style which is substantially more frequent, has a slightly tighter point range (the way I have defined it anyway) and has a bit better chance of reaching the best strain.

It might be but I think Ekren sucks after playing it for a while and talking to other people who tried it.

I am really tempted to try this flat 2 leve bids with combination with multi for example.

[straube]

I think some of those statistics are misleading. For example, I could open 2H with an unspecified 4333 hand and partner could also guess the best fit most of the time, but I think I've opened too high. The stats leave out the power of having a 6-cd suit. Besides which, I ran both the 6H (less side 5cd suit) and the 5H332 hands using the same point range of 7-11 and got 1.37%. So the difference between the two frequencies has to do with the point ranges and not the patterns.

[Fluffy]

the 1.88% number of the first one looks very very low to me, I supose you double checked your math but it still surprises me a lot.

[Flameous]

straube certainly mentioned the most important point. Point of pre-empts isn't just to expect finding a fit but having some actual playing strength.
This actually makes me wonder where is the line that penalty(ish) doubles start to gain more to T/Os. I think it might well be the case with "flat" pre-empts.

There is one good flat pre-empt and that is 1NT

[Phil]

The "Flat weak 2" looks a little like a Bailey 2, except for the point range (8-11). The general parameters are 5-6 of the suit, 2-3 cards in the other major, and no more than 9 cards in two suits combined.

Baileyites play some interesting methods to find their best fit - new suits are NF, and a 2N response asks for the longest minor (2x - 3x is played as 'invitational').

[awm]

I don't really mean to suggest that these alternative preempt styles are necessarily "better." There is a lot that goes into making one preempt style better than another, including safety, ability of responder to find the right level when holding a good hand, ability to further the preempt, difficulty of devising a defense, and (perhaps unfortunately, especially for calls that show length in the suit opened) legality of methods.

However, there are some maybe interesting observations here:

(1) Knowledge of opener's minimum length in a suit other than the one opened, even if only guaranteeing 3+ cards, can help a lot in scrambling to a good spot.
(2) A general agreement to open "five card preempts" is not very sound. People who play this are after "high frequency" but might do better to play some 2-suited preempt.
(3) Balanced or semi-balanced hands are really very frequent. If you want high-frequency two-level preempts you should look into including some of these hand types.

[gnasher]

awm, on 2012-January-02, 11:30, said:

I don't really mean to suggest that these alternative preempt styles are necessarily "better." There is a lot that goes into making one preempt style better than another, including safety, ability of responder to find the right level when holding a good hand, ability to further the preempt, difficulty of devising a defense, and (perhaps unfortunately, especially for calls that show length in the suit opened) legality of methods.

I think you've omitted the most important things: the probability that the opponents have a choice of strain or level, and the likely gain if they choose badly.

[Free]

What about the super aggressive Lorenzo two's? 0-7HCP (never a good hand, so no AK, AQ or AJT), 4+♥, ♥ >= ♠, longer m possible. I guess frequency will be very high, but chance to bid the best fit is quite small compared to other methods.