[mike777]

Pros and cons of using Flannery?

[DavidKok]

Pros:

• You can play that 1♥-1♠ shows 5 cards at reduced/minimal cost. Opener will opt for 2♦ with 4♠5(+)♥ weaker-than-reverse, so that on 1♥-1NT* (may contain 4 spades) opener either doesn't have 4 spades or is strong enough to introduce them anyway. The 1♥-1♠ start to the auction is notoriously tricky as both majors are in play (more so than over a 1m opening, even, as a 1m opener almost never has a 5(+)cM) and neither side is limited.
  
• You can decide to combine the above with Kaplan Inversion, notably KI5, to gain even more bidding space and resolve more hand types. This makes sense from a frequency perspective as well, as there are far more hands that would respond 1NT to 1♥ than there are hands that would respond a 5(+) 1♠. I think this also holds without Flannery, but the case becomes stronger.

Cons:

• You lose the 2♦ opening for something else. In particular, it has good preemptive value, whether natural or as part of an artificial set of preempts. It's also somewhat popular as a strong opening, such as the Mexican 2♦. This is particularly awkward as Flannery hands are so rare, so you're trading a high frequency profitable preempt for a low frequency debatable constructive opening.
  
• Starting your Flannery auction at 2♦ is slightly inconvenient. Good continuations exist, but especially on invitational misfit hands it can be hard to decide whether to sign off or to push to the 3-level. Note that standard 2/1 with a semiforcing 1NT might bid 1♥-1NT; a.p. with some of those hands, so at the very least you're a level higher and it can only get worse from there.
  
• In my opinion, modern bidding theory has mostly caught up with any problems Flannery alleges to solve. The particular problem (1♥-1NT forcing and opener is stuck for a rebid with 4♠5♥ too weak to reverse) can be solved with a semiforcing notrump, Bart/Lisa, some flavours of Gazzilli, Kaplan Inversion, some combination of the previous, some wild options like limited opening systems or even just be ignored because it's so uncommon. I prefer the semiforcing NT.

[mikeh]

Some very good pairs use 2H as flannery which, ignoring the cost of losing 2H for other purposes, seems superior to 2D because LHO has to commit over 2H when he could pass 2D and expect to get another chance

Otherwise I agree with David in that I think flannery as a solution for problem that is at least partially addressed by other, more modern methods. As rarity of 4-5 modest openers, I think BBO has a big in its random hand generator. I seem to get a lot of flannery hands, far more than in real life

I played flannery for a long time but stopped more than 20 years ago and don’t mss it. It consumes a lot of valuable bidding space, but any that good at slam bidding, leaks a lot of information and takes away other uses for 2D (or 2H) which I think are more effective

[johnu]

mikeh, on 2025-November-05, 14:22, said:

As rarity of 4-5 modest openers, I think BBO has a big in its random hand generator. I seem to get a lot of flannery hands, far more than in real life

If you had no clue what Flannery was, you wouldn't remember them at the same rate. My guess is that when you pick up a 4=5=x=x opening, you consciously (or unconsciously) think that this could be a Flannery opening, so you remember those hands better than random hands.

[mikeh]

johnu, on 2025-November-05, 17:14, said:

If you had no clue what Flannery was, you wouldn't remember them at the same rate. My guess is that when you pick up a 4=5=x=x opening, you consciously (or unconsciously) think that this could be a Flannery opening, so you remember those hands better than random hands.

I’m well aware of biases. However, I play a fair amount of face to face bridge…just came back from a Regional….and my impression is very much limited to BBO. Indeed, I only encountered two Flannery hands in Whistler, one of which led to a silly result when the opps had a huge misunderstanding. LHO opened 2D, partner doubled (showing a defensively oriented strong notrump or better) and RHO passed with a bad hand. I’d been wondering how many diamonds to bid with my AJ9xxxx and a side Jack but RHO’s pass made it easy…I passed and was pleasantly surprised when that ended the auction. Apparently LHO believed that his partner’s pass suggested playing there. 1700.

[DavidKok]

You're telling me that people play an artificial 2♦ opening but haven't discussed continuations after the most common interference - a double in second seat? I am shocked and baffled, who could ever have predicted such a thing

As always, competitive auctions are more important than constructive ones. Focus a good amount of your efforts there if you learn Flannery.