[CamHenry]

If N opens:
1♣-2♥ 10-15, no 5cM, not 4-4 majors OR 11-13 bal / weak takeout or slam try in ♠
2♠-4♣ To play opposite weak hand / 4 or 6 CPs
4♠ No slam interest

If S opens:
P-1♦ 16+, excluding GF
1♠-2♥ 8+ (almost) any / Single-suited ♠ OR short ♥ OR both minors
2♠-2N Relay / single-suited option
3♦-3♠ Suit / no better bid
4♠ To play

So, in either case, we reach 4♠ by N.

[PrecisionL]

Upgraded Ultra Club Relay (C3)

p p 1♣ p
1♠ = 4+♥ or bal and 11+ hcp p 1NT = asking -
2♣ = Artificial canape with longer minor - 2♦ = asking -
2♠ = 5+♦ - 2NT = Relay - 3♦ = 1=4=5=3 -
3♥ = Beta - 3NT = 3 Controls -
4♥ All Pass

[Zelandakh]

PrecisionL, on 2013-February-28, 18:47, said:

Upgraded Ultra Club Relay (C3)

2♠ = 5+♦ - 2NT = Relay - 3♦ = 1=4=5=3 -

Again, have you changed the system here? Dan's site gives this 2♠ bid as showing exactly 5 diamonds (1453, 2452 or 3451). If you were to bid 3♠ instead of 3♥, would that be a stopper show (effectively asking for a club stop)?

[PrecisionL]

Zelandakh, on 2013-March-01, 03:33, said:

Again, have you changed the system here? Dan's site gives this 2♠ bid as showing exactly 5 diamonds (1453, 2452 or 3451). If you were to bid 3♠ instead of 3♥, would that be a stopper show (effectively asking for a club stop)?

Another good question.

Yes, the system was changed to C3 in 2009 so that responder could show 4♥ and 6+♣/♦ by bidding to 2NT (1-under) or 3♣.

3♠ is not defined in the system in this auction - this is a problem hand and opener has to take a position with responder possibly having a 5-4 hand with 5♥.

The probability that hearts are 5-cds is 10-4 in this sequence.

I considered the alternate auction: 1♣ - 1♠ - 2♠ = SAB - 2NT = 0-1♠ - ? is more of a guess.