[pirate22]

one is plying Sayc-better minor-and neg x's-lets assume 1diam can be 3 or 4 cards.
So you are Dealer and open 1 Diamond-next opp bids 1 spade---- pard now bids...
2hts,one assumes a 5 card suit-but how many points?
3hts------- is this now a reverse?APOLS NOT A REVERSE A STRONGER RESPONSE IS A BETTER WORD
2sp-------- is this asking for a stop?
x---------- neg ? how many points.
2n/t------- again how many points...
lets also assume no neg x's in agreement,does this alter values

[helene_t]

2♥ shows enough values to force partner to 2NT if he has 12-14 balanced so you would like to have 11+ points. But people tend to stretch in contested auctions. I think 2♥ shows a little more than 2♣ does because with long hearts you can make a negative double so you don't have to stretch.

3♥ is a jump shift, not a reverse. Most play this as weak (or as fit-showing, but that is certainly not part of sayc). Playing sayc I would assume strong jump shifts in competition but I might be wrong.

2♠ shows diamond support. I think it is game-forcing in sayc. Most advanced players play it as invitational or stronger. That is because 3♦ would be weak. But I think 3♦ is a limit bid in sayc.

x is basically a 1♥ bid. It shows 6+ or so. It can be a weak hand with more than four hearts.

2NT is a natural limit bid. 11 points.

[Zelandakh]

1♦ - 1♠ - 2♥ is natural and forcing. You can tweak the lower range a little but ~11+ would be expected with a pick up.
1♦ - 1♠ - 3♥ is not a reverse. How can it be when partner has only bid 1 suit? This is commonly played as a fit jump (diamond support and a heart suit) but other possibilities exist - in SAYC it is probably natural and weak for example.
1♦ - 1♠ - 2♠ is somewhat regional. Where I learned it shows specifically a good diamond raise; in other areas it is used as a general force which does not guarantee support. I think SAYC uses the latter but am not 100% sure.
1♦ - 1♠ - X is 4 hearts and any strength or 5+ hearts and too weak for an immediate 2♥ call.
1♦ - 1♠ - 2NT is invitational, 11-12.

If you choose not to play negative doubles but instead negative freebids then an immediate 2♥ shows the weaker hand type with long hearts and X the stronger. Hands with 4 hearts still double. Note that you should not call this method SAYC. If you are not playing negative doubles and also not playing NFBs then you are on your own.

[pirate22]

These replies are interesting-and proposes somewhat a little confusion...
what the opener wants to know from partner is 2 things are you weak or good.
what is our combined count..if my opener is 12-19-- has my partner got 6-14+ ....

So I have devised a way to get information from partner..
1d---1sp---x =8-11 any shape {so opener knows we are in the combined range 20-23
1d---1sp---1n/t=12-14 with a stop..........................................24 min
1d---1sp---2sp =12-13 with no stop.........................................24 min
2n/t=15+ may have may not have a stop...........................25+

Same applies if 1d---2cl but responder has bid 1 level higher to show the count.
THIS NOW facilitates weaker hands but still wants to compete.example...
taking into account the vulnerabilities 1d--1sp--2cl/2d/2ht/3d are less than 8 points.
originally it was called sputnik to show 4 hts and some points...
and a point raised one could be bounced by responder of the 1sp bidder,let them,opener
of 1d can punnish them with a reopening x-if other opp silent opener shows pard his natural rebid.
so 1d--1sp--x--p
2hts is not a reverse shows 4/5 d and 4 hts still 12 points min...........
its all to do with mathamatics.
another example responder holds AJ9852-xx-1073--Q87 and bidding 1d--2cl--2sp shows a hand less than
8 points awaiting pard rebid or pass..it takes the guesswork away-- "Pirate NEG x's full range"

[manudude03]

Sorry, I can't think of a nicer way to put it, but those responses really suck. There isn't a law anywhere that says LHO isn't allowed to bid. Some examples with your scheme:

The bidding goes 1D-(1S)-X-(2S) and you hold xx AQJx AQJxx xx. Do you bid 3H and hope for a fit (big trouble if you don't) or do you pass and possibly miss 4H when partner can't reopen again (Axx KTxx xx xxxx and 4H is a reasonable gamble, and thats a 7 count). Besides, 3H would logically be forcing, how else do you show a 6-4 18 count say?

The bidding goes 1D-(1S)-X-(3S) and you hold Axx xxx AKQJx Ax? You probably bid 3N, is partner supposed to know you're cold for 7NT with his AKQxxx of hearts and out (provided you have 5 diamond tricks)?

The bidding goes 1C-(1S)-2NT-(4S) and you hold x Qx AQJxx Axxxx, how are you going to work out where you belong? (give partner xx AKxxxx Kx KQx).

Admittedly, these are slightly exaggerated examples, but these hand types are not that uncommon.