[pilun]

This is a question on the meaning of terms.

After 1♣ - (1♠) - 1♠

not accepted, responder has few options.

Assuming nothing much is comparable, responder may choose to bid 2♠ in an attempt to keep opener in the game.
That's okay if 2♠ "specifies the same denomination".

Since 2♠ does not specify spades, responder is on his own. Is that right?

After 1♣ - (1♠) - 1♥

responder can presumably make a negative double, since "all" hands that are worth double would have bid 1♥.

Not quite "all". ♠xxx ♥Axx ♦KQx ♣Axxx
looks like a double to me. Is "nearly all" good enough?

[pescetom]

It depends partly on what the bidder thought he was doing when he bid 1S. If he thought he was showing spades he is out of luck, unless he can convince a generous TD that 1NT or 3S is comparable. If he thought he was showing hearts and a minor and has the right hand, then TD will allow 2S whether 1S was a mechanical error or a brain fart.

[mycroft]

Specifically due to two different laws:

• mechanical error: 25A, unintended call
  
• brain fart: 27B1a, 2♠ is the lowest sufficient bid that "shows the same denominations" as intended by 1♠.

Not really relevant to the player, but important to realize (because many times "brain fart" isn't replaceable by "unintended call". But might be replaceable by some other call!

[pescetom]

mycroft, on 2025-October-16, 10:06, said:

Specifically due to two different laws:

• mechanical error: 25A, unintended call
  
• brain fart: 27B1a, 2♠ is the lowest sufficient bid that "shows the same denominations" as intended by 1♠.

Not really relevant to the player, but important to realize (because many times "brain fart" isn't replaceable by "unintended call". But might be replaceable by some other call!

And also that quite often a player will claim "unintended call" when it was really a brain fart (or just a rash decision), especially if he has an "Undo" button at hand. My point was that for once the distinction is not relevant, but you do well to point out that it usually is and that the laws of this mind game are extraordinarily tolerant of brain farts

[mycroft]

Sorry to step on your line. It was clear to me that you knew, but WeAllKnow that people hear only what they like out of director's statements(*) - so I didn't want to leave an impression that "just because this time it's the same, it's always the same".

(*) Like the time it was explained to me that the announcement is "we will start the next round in X minutes" (or "be seated and playing when the clock goes to zero") and no use of the "b" word is to be used. Because if you say it, that's all the late pairs will hear, and they will *demand* the break they were "promised".