[nullve]

If a defender uses cards in one suit to signal for a different suit (as when giving suit preference), how does/should that affect the meaning of the cards he later plays in the signalled for suit?

[nullve]

The following almost happened against a spade contract the other day:

1. ♥A-(♥3)-♥J*-(♥9)
2. ♣A-(♣5)-♣3**-(♣6)

* easily read as discouraging both a heart continuation and the "obvious shift" to a diamond, so effectively a suit preference signal for clubs
** easily read as encouraging

Why like clubs twice here?

[MrAce]

 nullve, on 2018-April-01, 17:55, said:

The following almost happened against a spade contract the other day:

1. ♥A-(♥3)-♥J*-(♥9)
2. ♣A-(♣5)-♣3**-(♣6)

* easily read as discouraging both a heart continuation and the "obvious shift" to a diamond, so effectively a suit preference signal for clubs
** easily read as encouraging

Why like clubs twice here?

First of all, in order for a card to be SP in your example, the 3rd hand player HAS TO be known to hold at least 3 cards in that suit (in your example ♥ suit). That applies even when you cash an A and dummy has a single. Most rookies who have "expert" written in their card plays the cards here as SP. They do not consider the fact that there are so many situations that they can not afford to make a SP signal, particularly when 3rd player holds a doubleton or stiff in that suit.

Second, if you already signaled for clubs in your agreement, then card you play on ♣A should be the count of this suit.

[nullve]

 MrAce, on 2018-April-02, 10:19, said:

First of all, in order for a card to be SP in your example, the 3rd hand player HAS TO be known to hold at least 3 cards in that suit (in your example ♥ suit).

Agree, and the J happened to be from a known 4-card suit.

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Today I played a board where I

1) doubled 6♣ for the lead;
2) encouraged when the ace was played from dummy on partner's club lead; and
3) followed with the 3 from J63 on the first round of trumps (= suit preference for clubs if anything).

So I managed to signal clubs three times on the same board --- the first time already in the bidding.

[MrAce]

 nullve, on 2018-April-03, 15:54, said:

Agree, and the J happened to be from a known 4-card suit.

--------

Today I played a board where I

1) doubled 6♣ for the lead;
2) encouraged when the ace was played from dummy on partner's club lead; and
3) followed with the 3 from J63 on the first round of trumps (= suit preference for clubs if anything).

So I managed to signal clubs three times on the same board --- the first time already in the bidding.

So in your example, when I dbl 6♣ I already signalled for ♣. when pd leads it and dummy plays the A, I would give count so if pd holds the hand he knows whether 2nd club can be cashed or not.
Only thing that may cause problem is when you double 6♣ with QJTxx(x) and you really do not want ♣ continuation, then you should have start with ♣ Q at T1 denying K if you really want a shift, otherwise still give count.