[shnk]

1)
2♣-2♦
2♠-?

The 2♦ response to 2♣ is game forcing (2♥ is negative)
3♠ is stronger than 4♠ here.

2)
2♣-2♦
3♣-?

Is 4♣ stronger than 5♣ here?
Can we ever stop in 4♣?
If its relevant, we do not play kickback.

[fromageGB]

 shnk, on 2013-July-16, 01:08, said:

1)
2♣-2♦
2♠-?

The 2♦ response to 2♣ is game forcing (2♥ is negative)
3♠ is stronger than 4♠ here.

2)
2♣-2♦
3♣-?

Is 4♣ stronger than 5♣ here?
Can we ever stop in 4♣?
If its relevant, we do not play kickback.

1) Yes, 3♠ stronger than 4♠, but if spade support is not good, perhaps 2NT would be better than 4♠ in case opener has a second suit. You can always bid 4♠ later.

2) Do you want to be able to play in 4♣ when you have a positive to a 2♣ open? I don't, so as opener is single suited I would bid 4♣ with club support so that opener may cue or ace ask. If I had a hand a trick better than a minimum positive, with club support I would jump (say 4♦) as a cue.

[PhilKing]

 shnk, on 2013-July-16, 01:08, said:

1)
2♣-2♦
2♠-?

The 2♦ response to 2♣ is game forcing (2♥ is negative)
3♠ is stronger than 4♠ here.

2)
2♣-2♦
3♣-?

Is 4♣ stronger than 5♣ here?
Can we ever stop in 4♣?
If its relevant, we do not play kickback.

You state 1) as a given, but it ain't so. Some of us just do not play fast arrival, and in this auction there is pretty much no upside to the method. I play as follows:

3♠ = positive. At least a decent slam try
4♠ = good trumps, nothing else. eg AJxx and no outside control.

With a minimum for 2♦, just bid 2NT and take it from there. Jumping to four is crazy. Say you hold:

♠Qxx
♥xxx
♦xxx
♣KJxx

Partner's next bid might be 3♣, and now your pile of dreck turns into a monster.

In 2) you can do much the same thing:

4♣ = genuine positive
5♣ = good trumps, nothing else

With a so-so raise to 4♣, bid 3♦ (Staymanic) and then 4♣ on the next round. And no - of course you can't stop in 4♣ after responding 2♦, but you can after bidding 2♥ showing a bust.

[Zelandakh]

In 1, I like to play an old-fashioned idea where the 4♠ jump denies a key card. Notice that you also have 2NT followed by 4♠ available as a second way of showing a minimum hand with spade support (albeit sometimes less clearly).

In 2, I play 4♣ as conditional Blackwood. Opener responds 4♦ with a bad hand for slam in context or gives key cards with a good hand. Since you almost certainly do not play that, 4♣ as a general raise with slam interest is fine. Catering to stopping in 4♣ after a 2♣ opening and positive response is pretty silly. OTOH, getting extra usage out of the 3♦ gadget au PK is a fine idea.

[Fluffy]

forget about playing 4m, 4, is a dreadful contract, 4m is used for slam purposes.

[fromageGB]

 fromageGB, on 2013-July-16, 04:29, said:

... as opener is single suited I would bid 4♣ with club support so that opener may cue or ace ask.

 Zelandakh, on 2013-July-16, 05:27, said:

In 2, I play 4♣ as conditional Blackwood. Opener responds 4♦ with a bad hand for slam in context or gives key cards with a good hand. Since you almost certainly do not play that...

 PhilKing, on 2013-July-16, 04:52, said:

... With a so-so raise to 4♣, bid 3♦ (Staymanic)

Actually, with my "system orientated" partner, I play the conditional ace ask as Zel suggests (following an earlier Zel post!) in other situations, but not in this. Opener has the hand that can decide whether 12 or 13 tricks are for the taking, not responder. Therefore it needs to be opener that asks. 4♣ natural is better in my view. If playing 4NT for aces, as the OP implies, I would jump cue bid with a trick better than a minimum positive, but playing kickback as I do, 4♣ could also be the stronger hand.

The 3♦ bid is a fine idea, but needs specific partnership agreement with a "system orientated" partner. With a normal partner I am sure 3♦ would be taken to be natural. You don't want partner raising it to game.