From a preemptive POV what matter are the critical cases, cases where using a specific bid make a difference compared to alternative. Consider 1NT–2H—3S as a super accept, how often 3S stop opps from finding a good 4 level contract ? Most of the times you can bid 2S and compete to 3S to reach the same position with sometimes extra information. However if the 3S bid allow you to find game that you would miss its different.

3M is the best preemptive bid (so it need to be frequent) but since there is no counter game try available it need to be precise for the constructive purpose. 5-7DH is probably the sweet spot. If you use 1S-3S as 7-9 than its unlikely opps were able to compete to the 4 level anyway and if you 1S-3S as 0-5 the bid is too rare (for preemptive purpose) and imprecise (for constructive purpose).

3M-1 should cover the other bottom range. If you play 3M as 0-5 than 3M-1 should be the mixed raise and vice versa. However 3M-1 is a forcing bid so no reasons to NOT put a GF hand in it as long as its a hand that will keep bidding over 4M if opener raise to 4M.

How you use 2NT or 3C or other GF raises is unlikely to matter as long as you respect bidding space principles.

Like if you think 3♦ is forcing only to 4m.

Like if you think 3♦ is 100% GF

I think XX with a 5 card suit isnt that bad as long as you have a strong desire to punish the opps, they are vul +200 is usually a good MP score so XX with a prime 3514 is normal.

However after a XX that suggest defending further double are penalty (not when you play Double pass inversion) and pass become the takeout hand or not sure what to do hand. If you play XX turn penalty on and you dont play FP “on” than you don't have a takeout X available so north is endplayed himself with his 25?? shapes in the majors. If the XX promise at least 3 cards in the others suit than there is a case for not playing FP however I would still X with south hand since I like my chances at +200.

Its always the same trilogy

a) X is pen —pass is forcing this lose the ability to defend undoubled. Regular forcing pass.Most common when our side promise GF values

b) X is pen —pass is non-forcing this lose the takeout double.This one should only be used when partner hand is well defined.

c) X is takeout—pass is not forcing = this lose the pen X
most common.

d) X is takeout/dsip— pass is forcing = this lose the ability to defend undoubled. This is dpi double pass inversion and its very similar to regular forcing pass.

a&d are almost equivalent. If you XX with a doubleton in a side suit I think its clear that you cannot lose the takeout double. Playing “B” is dubious unless the initial XX promise at least 3 cards in all side suits.

Either its a FP situation or a double is takeout. I assume north didnt X because it would be penality so south must bid since it should be a FP situation.

“”book“ action is to make a negative double”

If opener jump to 3S he shouldnt have a ♣ stopper (with 2 places to play you make a 3♣ cuebid) so you can bid 4H and partner will understand you have 6H+2/3D.

If you have the same hand but with ♦ singleton or the ♣A instead of ♦A now we have a problem.

IMO its safer to bid a flawed 1S/2C in round one rather than make an offshape double and correct one level higher.

If we simply compared it to a simialr but more frequent auction like

(1Y)–P–(3Y)–4S where 3Y is a preempt.

Than we see why 4S cannot be weak.

I think you are more likely to have a good minor than a good major because its easier to overcall 1M or to preempt 2M. But the difference is probably very small.

“The first double is a lead director”

A little bit off topic but imo favorable unpassed hand a natural bid is more important than lead direct.

If east X suggest bidding 4S over 4H than its likely that west will be able to bid 5S instead of 4S making life significantly harder.

Also I think that the best lead directing are short suits like KQT,KQ9,AQT but its dangerous to make a lead directing at the 3 level on a 3 carder if the opps know how to use their XX. Making a lead directing X agaisnt a suit contract with a lenghty suit like KQxxx is often helping offense more than defense.

I would play X of 5S suggest sacrificing.

South got UI because north called the director. For my partnerships bidding 2S after we denied 4M tend to show 31?? type of hands where we dont want to risk a dsip/takeout double. So 2S is indeed natural but it show 3 cards.

South does have a hand where its tempting to bid 3S but passing with a flat hand is surely LA.

opener hand was
AQJxx
A
xx
Axxxx

game make even if clubs are 3-1 and trumps are 4-1, you just need to be careful and play clubs instead of trumps and discard ♦ rather than ruff if they try to tap you in hearts.

Opener tought that responder was 2??3 or 2??4 not good enough for a false preference.

1Nt isnt forcing, if opener bid 2C on a 3carder its because hes going to be 15+ 6??3 and he wont pass 3C anyway.

♦K is onside but ♠Q is offside but show up double squeeze = 20%

Ax
8
—
x

KJx
—
x
—

If we assume ♥ are 5-1 and that east got ♦JT than we have these odds.

both onside 30%
only ♠Q onside =26%

♠Q onside but ♠ 4-3, 3%

west ♦ that are Kxx/Kx = 25%

You already loss a ♣ so you cannot afford to lose a ♥ to get a ♥ trick.
Because of the 1st trick east is likely longer in ♦. EAst have the ♦K is more likely than west having Kx/Kxx in ♦

I simply do exactly as a play of the hand problems from an old book where the contract is ridiculous, so I know I would never be in this contract but it doesnt stop me to do my best to find the best line.

Passing and X is fine, most of the time the bidding will comeback in 2♥.

I think a delayed 3M got to show 4♠+long club and X of 3H show the same but stronger.

I prefer to simply bid X or at least bid 3S rather than 3H because Im 100% certain that my partner will not play me for 5S/5m and I prefer to show defensive values rather than only offensive values. But its no big deal either way.

3rd part look like an easy pass, partner could have 3S and singleton club.

If we decide to play ♠ ace and rely on ♣ finesse we wont be able to take double ♦ finesse so its not as clear as i tought.

♠A, low ♥ to K,♣ finesse, ♦ to A repeat club finesse play a 3rd club and hope for ♣ 3-4 or probably better to just cash 2 round of trumps. Even if trumps are 3-1 we still have some hope to have only one ♦ loser.

Starting with ♦J is also quite likely to induce a cover.