[aguahombre]

Zel's concerns about the 1C vs 1D debate are part of what I meant when I talked about systemic issues and inferences. The pairs who believe the auction:

1m (1S) X

should guarantee both unbid suits have it easy, and whether opener bid 1C or 1D with (3-2) 4-4 doesn't really matter. But, if 1m (1S) X only promises responding values and a hand which would have responded 1H --- then there is a big trade-off. Responder with (say) KXX AXXX XXX XXX has nowhere to go if Opener will rebid 2C after opening 1D on XXX KX AJXX KQXX.

The 1C openers also have available a 2D rebid after that NEG Dbl to show true reverse strength. The downside is that we someimes play it in 1NT with no spade control; but on frequency with no spade raise from RHO, I don't believe we care.

[Cascade]

Zelandakh, on 2013-October-15, 17:55, said:

but many systems (including Acol) choose to open the 3343 hand 1♦. I suspect that has more to do with tradition than with any intrinsic merit.

I am pretty sure there is intrinsic merit in opening your longest suit.

[Zelandakh]

I agree with you but would add the qualifier "when there is an interest in playing in that suit". Whether this qualifier applies to diamonds in a 3343 hand is perhaps a different matter.

[mycroft]

All the "we intend to play in NT, not our suit" bits are fine and all, but opponents keep finding overcalls, sometimes in suits we don't have stoppers in.

NA-bias here - this is one reason we will bypass an unbid major to bid NT with a 15-17 balanced hand; everyone else is starting there. Also, if they overcall in our stopperless suit, we're behind (frankly, if fourth-seat bids at all, we're behind - this is the Achilles' heel of weak NT systems), so we'd better get something out of it, and that something is "more better places to play than the 1NT-p-p-overcall".

Now, K/S bias - I'm not playing 4-card majors. If you are, then there are hands that just bid better having clubs available to bid weakly, especially if partner will hesitate to bid a bad 4-card major. We 5-card majorites have to just live with amorphous minors. Some are so happy with them that they make one worse to make one better - either by playing a strong club, or 1♣ "clubs or balanced" with transfer response, or Montreal Relay, or whatever.