[Swammerdam]

I have some questions about bidding agreements in the context of SAYC. I don't expect unanimity: the variations and correlations will be interesting.
In all cases, assume that the opening bid comes in 1st- or 2nd-chair. I've provided questions (1) - (8). Please feel free to add your own (numbered) questions to the thread.

(1) How do you respond to One Club holding 4 diamonds and a 4-card major? (And do you play checkback Stayman?)

(2) I assume 4th-suit bid by responder is forcing and may be artificial. Does it promise a rebid? Is it forcing to game?

(3) How about (opponents silent) One Club - One Heart - One Spade - Three Clubs? Forcing? Promises a rebid? Forcing to game?

(4) Inverted minors in SAYC? Good idea?

(5) In response to One of a Major, what do 2NT and 3NT mean? (I know SAYC specifies Jacoby 2NT but wonder what good players actually play.)

(6) I always have 5+ cards when I open One of a Major (in 1st or 2nd seat) but sometimes am tempted to open a very good 4-card Heart suit when the alternative is a poor Diamond suit. Comments?

(7) With 5-5 in Spades and Clubs I often open One Club to keep the bidding low. Am I alone on this?

(8) I might reverse as opener when I have an Ace more than needed to open. That reverse is not quite forcing. Am I out of line? In another thread I see that the reverse is now treated as stronger than this and is forcing for one round.

[smerriman]

Are you sure you mean 'in the context of SAYC'? SAYC has no flexibility; it was designed so that an unknown partnership could play together without needing to have any discussions. Most people who claim to play SAYC don't actually play SAYC at all (e.g. 1m - 2N is game forcing in SAYC).

Most likely you didn't intend to use the term SAYC at all, and are talking about a more general Standard American system, where a 2/1 bid is not game forcing - correct? You'll probably find it hard to get a sample of 'good players' who play with that restriction, though most of your questions are applicable to systems other than SA as well.

[awm]

(1) With 4♦ and four of a major, you have a choice of responses to 1♣. My tendency is to bid the diamonds if they are much stronger than the major (helps partner evaluate game or slam) or if my hand is very strong (such that 6♦ might be a possibility if we have a fit there). Otherwise I prefer the major.

(2) 4th suit is artificial and forcing one round in SAYC, but not necessarily to game. However, most modern partnerships prefer forcing to game (mine included).

(3) Jumps to the three-level in suits that your side has already bid are normally invitational to game (but not forcing). This includes 1♣-1♥-1♠-3♣.

(4) Inverted minors are fine in SAYC.

(5) SAYC has 1M-2NT as a game-forcing raise. These days it's popular to play 2NT as an invitational or better raise, but you need somewhat more complex rebids by opener. It's quite unusual to encounter any pair that doesn't play 1M-2NT as a raise of some variety, in my experience. I think standard is to play 1M-3NT as a 4333 hand with three-card support and minimum game force values, but this doesn't come up a whole lot. A treatment that I like is to play tiered splinters, where 1♥-3♠ or 1♠-3NT shows a very minimum splinter in any suit, with 1♥-3NT being a better spade splinter, but of course this is very much not SAYC.

(6) I don't recommend opening four-card majors in 1st/2nd seat when playing a generally five-card major system. Suit length is really more important than honor location in most auctions.

(7) Opening 1♣ with 5♠+5♣ is a very old-fashioned style; most people today open 1♠ because of the frequency of competitive auctions and the desire to keep opponents out and/or minimise the information you give them on simple auctions like 1♠-3♠-4♠. Of course opening 1♣ could work better if opponents pass the whole time and you get to rebid 1♠ and then 2♠ and partner knows this doesn't promise 5♠-6♣ for you like it would for most people.

(8) Reverses are normally played as forcing (barring a strong club system or something like this) and show more than a minimum opening. There's some disagreement about the lower limit (I prefer more like 16 points while some people prefer more like 18) but there's no upper limit so partner should never pass.

[P_Marlowe]

Hi,

#1 Major, basically this means, if you start with diamonds you show a 5-4 shape,
when you show a 4 card major.

#2 Most Exp. partnership have moved towards GF, I prefer inv.+
The reason they moved, they claim it is simpler, which is wrong, but you have simpler
start, can postpone some indepth discussions, ..., sometimes you forget you still need
those.

#3 Inv.

#4 Sure, but a bit overrrated

#5 You need some form a forcing raise for the major, and 2NT is quite sensible.

#6 In 3rd seat this maybe ok, but unless you want to swith to 4 card major, 1M showes 5+

#7 No, but this is a dying style, but zombies are every where, and as always there are pro
and cons, but your partner needs to expect this, and without discussion, start with spades

#8 No, this is mainstream

With kind regards
Marlowe

[Swammerdam]

smerriman, on 2024-June-06, 21:19, said:

Are you sure you mean 'in the context of SAYC'? SAYC has no flexibility; it was designed so that an unknown partnership could play together without needing to have any discussions. Most people who claim to play SAYC don't actually play SAYC at all (e.g. 1m - 2N is game forcing in SAYC).

Most likely you didn't intend to use the term SAYC at all, and are talking about a more general Standard American system, where a 2/1 bid is not game forcing - correct? You'll probably find it hard to get a sample of 'good players' who play with that restriction, though most of your questions are applicable to systems other than SA as well.

Thank you for your comments, smerriman!

Obviously I meant "in the context of a system based on, or similar to, SAYC."
In the Casual games at BBO, many write "SAYC" but very few of those even seem to know SAYC! My immediate need is to play with experts who accidentally fall into a Casual game.

Assuming https://web2.acbl.or.../play/SP3%20(bk)%20single%20pages.pdf is the definition of SAYC I see

Quote

a pair could use the SAYC as a base and make one or two modifications.

I also see

• reverses by opener are "16-18" points. (I play about 16-20. I see in another thread that many play it as about 18-20.)
  
• An acknowledgement that 4th suit is forcing and may be "conventional" BUT Zero mention of subsequent auction. Surely a pair playing "SAYC" should be allowed or even encouraged to answer my question (2).
  
• I see no answer to my question (3) either.

For these reasons I did not find your response particularly helpful.
Fortunately I see some very recent responses which I will read now.

[Swammerdam]

A brief note about me: I was an avid tournament player circa 1970. I was often seeded in ACBL Sectionals then, but spent some decades not playing, and by now my brain's focus and short-term memory are in decline. I am fortunate that the bidding system then most common in Northern California was VERY similar to SAYC. But some of my ideas are old-fashioned now!

Thanks to awm and P_Marlowe for the responses! This will be very helpful for me.

I'll make two specific comments:

awm, on 2024-June-07, 01:21, said:

(2) 4th suit is artificial and forcing one round in SAYC, but not necessarily to game. However, most modern partnerships prefer forcing to game (mine included).

(3) Jumps to the three-level in suits that your side has already bid are normally invitational to game (but not forcing). This includes 1♣-1♥-1♠-3♣.

There was no agreement on this in 1970. I felt that one or the other of these two should be a game-force and the other not. I am used to playing 4th suit as NOT promising a rebid; opener's 3rd bid is supposed to limit his hand. This seems wise since sometimes the 4th suit is NOT artificial and you want to bail out quickly with a misfit.

awm, on 2024-June-07, 01:21, said:

(7) Opening 1♣ with 5♠+5♣ is a very old-fashioned style; most people today open 1♠ because of the frequency of competitive auctions and the desire to keep opponents out and/or minimise the information you give them on simple auctions like 1♠-3♠-4♠. Of course opening 1♣ could work better if opponents pass the whole time and you get to rebid 1♠ and then 2♠ and partner knows this doesn't promise 5♠-6♣ for you like it would for most people.

I've opened 5-5 with One Club several times at BBO recently and suffered no mishap. Maybe I've been lucky. BBO Casual players often seem aggressive, but maybe experts are even more aggressive!

[smerriman]

Swammerdam, on 2024-June-07, 02:10, said:

For these reasons I did not find your response particularly helpful.
Fortunately I see some very recent responses which I will read now.

My answers to your questions differed substantially depending on your meaning; one for the true SAYC definition, one for what I'd general assume/play with someone that said they wanted to play SAYC, and one what I would prefer to play in a more general SA system, thus the reason I asked for a clarification. Like in bidding, you don't have to describe your entire hand in a single bid!

I now take it you wanted the last of those:

1) I prefer 1♥, and XYZ.
2) I prefer GF.
3) GF for me, given I play XYZ (with 2NT a puppet to 3♣).
4) Yes, some forcing of forcing minor raise is required, and standard inverted minors is fine for me compared with the alternatives.
5) 2NT Jacoby; 3NT needs to be something very tightly defined; some form of splinter seems like the best use for it that I've heard to date.
6) Maybe a very rare hand, but I don't recall the last time I opened a 4 card major.
7) Definitely 1♠ for me
8) Definitely forcing for me. There are many hands worthy of even opening 2♣ strength wise, but where the bidding would get far too high before you can describe your hand if you did. Opening 1m and then forcing with a reverse makes these a lot simpler.

[P_Marlowe]

P_Marlowe, on 2024-June-07, 01:33, said:

#8 No, this is mainstream

Just to be clear, forcing, just how far is up to debate, it seems
promising another bid is exp. standard, i.e.

1C - 1S
2H - 2S

2S cannot be passed, if reverses promise another bid, ..., and not being
able to pass 2S is common, ... I deviate, but I am in a (very small) minority
here, being the lonesome rider is ok for me.

[mw64ahw]

Standard American is based on the 5-card Major bidding system developed by Charles Goren and his contemporaries. Many of the questions you ask suggest you learnt bridge from the same source as me. The SAYC standard introduced by the ABCL in the 1980s.
My current system has developed significantly so that while it may be based on Standard American (i.e. 5-card Majors 2-level responses game invitational rather than 2/1 game forcing) in barely resembles anything that I originally learnt.

Coming back to your questions
1) I play a Majors always first approach approach so would always show Hearts, but there ae other styles which would show 5♦ before the 4♥ when GI/GF. In addition many now play Transfer Walsh, which shows ♥/♠ via 1red. I do not need Checkback Stayman.
2) Bidding a 4th suit always has meaning for me, but not necessarily as a 4SF nebulous bid.
3) 1♣-1♥-1♠-3♣ would be a limit raise so invitational. Use 4SF otherwise.
4) Inverted minors is one of mooted extensions to SAYC. I think BBO solitaire uses this approach if you want to try it out. Others can correct if I'm wrong
5) I use 1♠-2N as Limit+ 4+, but this uses a low information approach rather than Jacoby type bids. 1♥-2♠ is my the equivalent for symmetry.
1M-3N was originally choice of games, but there are other alternatives available such as support with an unspecified void, a minor suit pre-empt etc.
6) Goren originally suggested you consider opening 1M with 44M if your high card points were concentrated in the Majors, but this is not an approach I play
7) Again this suggestion is found in Goren's book, but not something I play. Incidentally I did have it bid like this against me last week with 5-5♣♠, but they were playing Acol.
8) There are limited hands I would reverse on with 16, but this may be playing lighter openers. I play it as F1.

[helene_t]

(1) How do you respond to One Club holding 4 diamonds and a 4-card major? (And do you play checkback Stayman?)
In principle 1♦ but I wouldn't call it a system violation if you bid 1M, there can be several good reasons for doing so, and most SA styles prescribe 1M so you could argue that it is just one of those things that don't need to be in the SAYC booklet because everyone knows it.

(2) I assume 4th-suit bid by responder is forcing and may be artificial. Does it promise a rebid? Is it forcing to game?
I think forcing to game, there is no explicit exception for this.

(3) How about (opponents silent) One Club - One Heart - One Spade - Three Clubs? Forcing? Promises a rebid? Forcing to game?
Not forcing.

(4) Inverted minors in SAYC? Good idea?
Maybe a good idea, but it is not SAYC anymore if you modify it

(5) In response to One of a Major, what do 2NT and 3NT mean? (I know SAYC specifies Jacoby 2NT but wonder what good players actually play.)
Jacoby, indeed. 3NT is presumably to play. Established partnerships have more economic follow ups, maybe something including 3♣ as a generic non-slamish hand, but then they aren't playing SAYC.

(6) I always have 5+ cards when I open One of a Major (in 1st or 2nd seat) but sometimes am tempted to open a very good 4-card Heart suit when the alternative is a poor Diamond suit. Comments?
No. Maybe with 11 points in 3rd seat, that is more a style thing than a system thing. But SAYC doesn't play Drury and 3M is the only limit raise even by a passed hand so you need to willing to play 3M in a 4-3 fit, or just gamble that it won't happen too often.

(7) With 5-5 in Spades and Clubs I often open One Club to keep the bidding low. Am I alone on this?
In SAYC you don't do that.

(8) I might reverse as opener when I have an Ace more than needed to open. That reverse is not quite forcing. Am I out of line? In another thread I see that the reverse is now treated as stronger than this and is forcing for one round.
A reverse is certainly forcing, in most modern styles it also promises a rebid but SAYC doesn't say so explicitly, I would assume a reverse is just forcing for one round in SAYC.

[Swammerdam]

Thanks again for the excellent and helpful responses.

Yes, as one of you mentioned some of my ideas come from old-fashioned ACOL. Some people described the Northern California bidding 55 years ago as "Standard American with Acol tendencies." (Of course that was when Goren and Roth-Stone didn't even play limit major raises.) I even read and admired an old ACOL textbook.

With all the forces your responses describe I'm surprised you don't get too high, or miss fits! And I do like my approach to 4th Suit Forcing:

Swammerdam, on 2024-June-07, 02:34, said:

I am used to playing 4th suit as NOT promising a rebid; opener's 3rd bid is supposed to limit his hand. This seems wise since sometimes the 4th suit is NOT artificial and you want to bail out quickly with a misfit.

On the matter of responding with a 4-card diamond suit before a major the SAYC pamphlet has "Bidding at the one level is up-the-line in principle." And, if I recall correctly, this was a default principle in my circles 55 years ago.

Follow-up question: If you open One Club and partner responds One Diamond do you usually now show your 4-card Major?

[P_Marlowe]

Swammerdam, on 2024-June-08, 00:37, said:

<snip>

Follow-up question: If you open One Club and partner responds One Diamond do you usually now show your 4-card Major?

Both styles a ok, but the trend goes toward clarifying openers hand type bal. / unbal., i.e. even with 44 in the majors
bidding 1NT is not uncommon.
Obviously you need something like NMF, if opener showes a major and responder raises, you also know responder is unbal.

[blackshoe]

A reverse by opener after a one level response in SA is forcing for one round and should have about 18 points up to whatever hand of that shape doesn't open 2♣. After a two level response the minimum strength requirement is about an ace lower. Playing 2/1 GF, a reverse by opener after a 2/1 response has no minimum strength requirement (except of course that you opened the bidding) because the auction is already GF.

A bid is either forcing or not forcing. "Not quite forcing" means not forcing.

[akwoo]

Swammerdam, on 2024-June-07, 02:34, said:

BBO Casual players often seem aggressive, but maybe experts are even more aggressive!

I would say that the biggest bidding difference between now and 25 years ago is that more players understand that -100 is better than -110. Of course there are still a lot who don't, or can't psychologically bring themselves to act like they do.

[Swammerdam]

Thanks for the comments!

I define SAYC as https://web2.acbl.or.../play/SP3%20(bk)%20single%20pages.pdf
If there's a more recent definition of SAYC, please tell me.

As I compare approaches, I see mine tend to be the practice from several decades ago. And indeed "SAYC" dates to the 1980's.
Still I will defend some of these SAYC approaches.

smerriman, on 2024-June-06, 21:19, said:

Are you sure you mean 'in the context of SAYC'? SAYC has no flexibility; it was designed so that an unknown partnership could play together without needing to have any discussions.sample of 'good players' who play with that restriction, though most of your questions are applicable to systems other than SA as well.

OK. I choose to play Pure SAYC !

However, the pamphlet omits many answers and dictates answers differing from expert practice as written here. Those who wondered about the meaning of "within SAYC (context)", now know I play PURE SAYC. If your partner was struck with lightning and I was the only substitute available, would you be willing to play it with me? What are the (at most three) addenda or corrections you would insist on for our convention card?


Two differences stand out between Pure SAYC and the recommendations in this thread.

(1) In the pamphlet, a reverse is 16-18 and thus clearly non-forcing.
The SAYC pamphlet dictates, Quote:
. . . . Rebids with a medium hand (16–18 points):
...
. . . . . . . Reverse in a new suit, i.e., bid a new suit at the two level which is higher ranking than the opening suit;

Stupid as it MIGHT seem, a Jump Reverse is needed for unconditional force! IIRC this was typical prescription in circa-1965 textbooks.


To trivialize, most of you play the reverse as 19-22 "Goren-like points" or thereabouts, Is that correct? I'll have about 15-19 HCP, sometimes with 14 or even less (perhaps AQJxx AT9xxxx - x) if I like my shape. Responder will strive to bid again, but may Pass when his first response was a courtesy response with a mediocre 4-6 HCP.

Whether you LIKE the system or not, will you agree that my method is more the explicit "SAYC method"?

(2) Bidding up the line in Principle.
Also, while not INSISTING on the 1D response with various 4-4's or even 4-4-4's, it is certainly ALLOWED in SAYC, and may seem good tactic for various reasons. I ask that you DO show your 4-card major rebidding after IC-1D in "SAYC". By showing your suits at the 1-level before you even get up to 1NT, you take advantage of bidding room! (Yes, the opponents may counter with aggressive overcalls but that's all the more reason to describe your distribution to partner.)

Did one of you say you'll bid a 4-card major before a 5-card diamond suit? I am horrified! :-)

(3) Another major difference between my method and recommendations here is that I play 4th suit by responder does not even promise a rebid, while most of you play it as game force! I'd like to discuss my approach, but await suggestions pointing to an existing or novel thread on that topic.

[Swammerdam]

Let me ask question (9), although it has little to do with SAYC per se.

Is a new suit by responder forcing after opponent intervenes (with Double, 1 NT or a suit overcall)? I recall these as forcing but some of the Casual BBO players do not think so.

There might be a case for suit non-forcing after a Double (if strong enough to force, you are strong enough for Redouble) or 1NT (if strong enough to force you might be strong enough to Double 1NT), but my partner passed in the auction 1C 1D 1S All Pass.

I'm afraid this may seem like a stupid question, but I've been out-of-touch from Bridge for decades.

[Stephen Tu]

Swammerdam, on 2024-June-11, 21:53, said:

OK. I choose to play Pure SAYC !

I'd recommend just learning 2/1. Practically no one any good plays SAYC. SAYC is only used for playing with pick-up partners online with minimal discussion, and 90% of the players have probably never read the pamphlet anyway, so you end up playing with someone who is playing "SA as I learned to play it", guessing on some of the ambiguous sequences, and hoping partner knows the conventions that are specified on the document. Serious partnerships in the US are nearly all 2/1 based, except for those playing strong club and a handful of outliers playing their own invented systems.

You have to know that SAYC was designed by committee for "only one system allowed" tournaments, that quickly died out from lack of popularity, and was basically a hodgepodge of semi-popular treatments at the time thrown together, not in any coherent fashion, leaving a lot of holes in the system. The pamphlet is a brief summary, not at all intended as a complete tutorial on how to bid. People were supposed to bring their own knowledge of Standard American to fill in the gaps on auctions not covered by the pamphlet.

It's basically an accident of history that SAYC gained traction online, the existence of the relatively brief summary allowed it to be digitized and distributed easily on the early days of internet bridge on okbridge, and it became a flawed but sort-of playable baseline for pickup partnerships.

Quote

If your partner was struck with lightning and I was the only substitute available, would you be willing to play it with me? What are the (at most three) addenda or corrections you would insist on for our convention card?

To me, the most glaring omissions for SAYC are:

1. Checkback mechanism for fit in a major after 1m-1M-1nt. Need to have some sort of NMF/checkback stayman/ XYZ type of thing. The vast majority of US experts these days have gravitated to a two-way checkback here with 2d as an artificial GF (regardless of minor opened), and 2c as a puppet to 2d to show invitational hands or certain minor signoffs depending on variation (sometimes also using 1m-1M-1nt-2nt as a puppet to 3c for possible signoff).


2. No forcing minor raise. (play inverted or something instead IMO)


3. Only playing negative doubles to the absurdly low level of 2S, with higher being ostensibly penalty. And "penalty doubles" of 4h/4s openings. This is all absurdly old-fashioned. These days way more doubles are assumed to be takeout oriented, and to way higher levels, it's just at higher levels partner is expected to leave them in for penalty way more often with flatter hands/not much offense.

Quote

(1) In the pamphlet, a reverse is 16-18 and thus clearly non-forcing.
The SAYC pamphlet dictates, Quote:
. . . . Rebids with a medium hand (16–18 points):
...
. . . . . . . Reverse in a new suit, i.e., bid a new suit at the two level which is higher ranking than the opening suit;

The pamphlet is just woefully incomplete, not at all comprehensive. No one played SA that way at the time, with reverses medium strength, limited, and NF, and needing to jump reverse to create a force. Note the pamphlet has no mention of jump reverses at all. Everyone considers reverse as one-round force and unlimited, but not GF, even back then, it's just that if you play SAYC it's a total guessing game what the follow-ups are supposed to be (since no Ingberman/Blackout/Lebensohl etc. specified).

Quote

Stupid as it MIGHT seem, a Jump Reverse is needed for unconditional force! IIRC this was typical prescription in circa-1965 textbooks.

Yeah this was no longer true by the 80s.

Quote

To trivialize, most of you play the reverse as 19-22 "Goren-like points" or thereabouts, Is that correct? I'll have about 15-19 HCP, sometimes with 14 or even less (perhaps AQJxx AT9xxxx - x) if I like my shape. Responder will strive to bid again, but may Pass when his first response was a courtesy response with a mediocre 4-6 HCP.

No absolutely not. It's basically like you said, normally 16/17+ but perhaps shaded with fit or extreme shape. Top end is only capped by 2c opener, could have 21/22 IMO as reverse shaped hands are often difficult to bid after 2c opener starting at 3 level, those just rare since rare to pick up such hands. Forcing and promises a rebid, but not GF. Whether responder is allowed to pass if they stretched to respond with a sub-minimum is a matter of philosophy and partnership agreement. I personally always bid again since opener may have fit for my 5cd major, and I am not one to stretch to respond holding only 4 cd major to bid.

Quote

(2) Bidding up the line in Principle.
Also, while not INSISTING on the 1D response with various 4-4's or even 4-4-4's, it is certainly ALLOWED in SAYC, and may seem good tactic for various reasons. I ask that you DO show your 4-card major rebidding after IC-1D in "SAYC". By showing your suits at the 1-level before you even get up to 1NT, you take advantage of bidding room! (Yes, the opponents may counter with aggressive overcalls but that's all the more reason to describe your distribution to partner.)

SAYC specifies up-the-line in the document, but again has partner read it??

Up-the-line bidding has mostly disappeared in the expert world; "Walsh" style, where 1d (even with longer diamonds) is routinely bypassed in favor of responding in a major unless holding GF values, predominates now. So much so that a decent number of hypermodern experts go further and play "transfer Walsh" over 1c, using 1d to show hearts and 1h to show spades, since they so infrequently bid diamonds now that this is a more efficient use of space.
I think the idea is that you want to not lose your major fit in case 4th hand throws in a preempt, also responding 1s in response to 1c can prevent a cheap heart overcall. Plus you gain a lot of concealment since most of your games are played in major or notrump and you often avoid disclosing extra side suit distribution information to the opponents which would only aid their defense. Gain concealment when you declare 1nt also.

Quote

(3) Another major difference between my method and recommendations here is that I play 4th suit by responder does not even promise a rebid, while most of you play it as game force! I'd like to discuss my approach, but await suggestions pointing to an existing or novel thread on that topic.

4th suit GF is a corollary of nearly all people playing a style where 2nd round jumps by responder (1c-1h-1s-3s, 1c-1h-1s-2nt, 1c-1h-1s-3h, etc.) are invitational only. When
all these auctions are inv, you more or less have to shunt all the GFs (that aren't suitable to jumping to game directly) into 4th suit forcing, and it's very awkward and space consuming to also include some inv hands into that and require opener to jump with just a little extra just to insure not being passed.
It is possible to play the other way, as old-fashioned Goren, with the second round jumps forcing, and 4th suit forcing mostly inv hands. It's just extremely hard to find partners willing to play that way these days. Only one of my partnerships ever tried this and I haven't played this style in almost 20 years, as it just hasn't been the default way people have learned for many decades at this point. 4th suit GF is just "standard" at this point, even though there can be arguable advantages for the other way on certain auctions.

[Stephen Tu]

Swammerdam, on 2024-June-11, 22:00, said:

Let me ask question (9), although it has little to do with SAYC per se.

Is a new suit by responder forcing after opponent intervenes (with Double, 1 NT or a suit overcall)? I recall these as forcing but some of the Casual BBO players do not think so.

Standard without discussion is that new suit is forcing if

-after double, at the one level.
-after a suit overcall.

But NF:

-after double, new suit at 2 level (redouble first with a force. experts often now use transfers here after 1M-x, but this is decidedly not a gadget in SAYC)

-over 1nt. (double with strong hand first, or cue 2nt with extremely distributional hands that want to set up force but not wanting to play 1nt-dbl)