July 9, 2018
The 2017 edition of the Laws of Duplicate Bridge brought in many small changes, and one huge one: Law 23, the Comparable Call rule. The intent is to preserve a bridge result in place of the rather severe penalties of earlier laws. It's not a bad thing, but we'll be adapting to it for quite a while.
Imagine this situation: LHO (Left-hand opponent) is the dealer, but you're distracted with a good hand and you put down a 1♠ bid. The director is called, and your bid-out-of-turn is not accepted by the opponents.
The director cancels your bid, and the auction reverts to LHO who passes. Your partner has no restrictions, but is not allowed to act on the unauthorized information of your 1♠ bid. Partner opens 1♥. RHO passes.
Now you're in the position of having to make a "comparable call" to a 1♠ opening bid. That is, your bid must show at least opening strength, and five or more spades.
You're stuck. The bidding systems I know of have no such bid in responder's seat. The 1♠ bid you started with, in responder's context, shows 6+ points and 4+ spades, and is not considered a comparable call according to Law 23. What would a 2♠ jump-shift be in your system? Whatever it means, it probably doesn't come close to describing a 1♠ opening hand. Most likely, there is no bid comparable to a generic opening bid once you become responder.
Any call you make, including a pass, will now bar your partner from the auction for one round (Law 31 A2(b)). Your best bet is probably to bid 3NT (or 4♥ if you can) and hope for the best. (By the way, no director can suggest that to you, so consider yourself informed now!)
But what if we adapted our bidding systems to Law 23?
What are you using jump-shifts for currently? Are you playing preemptive jump-shifts? Soloway? Goren strong?
What if our bidding system specified that a 2♥ or 2♠ jump-shift by responder promises 12-21 points and five or more cards in the suit? Then you would have a comparable call, and the partnership could continue bidding to its best contract.
I call this the comparable call jump-shift. ☺ (It might be easier to find a comparable call for a minor-suit opening, but I'm not sure!)
What if our agreements only include that meaning for the jump-shift in the event of an opening bid out of turn? I have a feeling that variation would not be allowed by any reasonable regulating authority.
Certainly it's not unreasonable to design your bidding strategy based on the laws of the game. I know of no limitations on the convention chart that would preclude giving a major-suit jump shift this meaning. It's difficult to put a statistical value on lapses of attention that cause a bid out of turn, but I think it's potentially more valuable than the jump-shift you're using now.