The tables below summarise the Granovetter defensive signalling system. This is an expanded "attitude" signalling system designed to allow you to tell partner on her opening lead and at certain other times whether you would or would not like a shift to what Granovetter called "the obvious shift suit." I have substituted the term "usual shift" for Granovetter's term,"obvious shift", since what may seem "obvious" to one person may not seem so obvious to another.
Granovetter Signalling System
The first table explains exactly what is the Usual Shift Suit, both at Suit Contracts and at No-trump contracts.
Dummy's Usual Shift Suit Suit Contract No-trump contract 1) The suit bid by one defender 1) Suit bid by defender
2) Dummy's shortest suit (unless it is declarer's suit)
2) Dummy's weakest three-card suit (Hxx or less)
(If two equally weak 3-card suits, the lower ranking is "usual".
3) If no weak 3-carder, then any doubleton
(If none of the above, weakest or lower ranking 4-card suit)
If each defender has bid a suit, use common sense in selecting your shift.
This second table below gives the meaning of partner's signal which can either be a high card, a low card or an unusal honour card.
Meaning of Partner's Signal High Card Low Card Honour Card
(If board has a singleton, for instance)
I like the suit you led OR I don't want a shift to the usual shift suit I don't have any interest in your suit OR I'd like a shift to the usual shift suit Please lead an unusual suit
(Or solid from here down)
When do you give these signals? The signal is given to partner's opening lead. The Granovetter signal replaces "count" which is not given, and it expands the concept of "attitude" beyond the conventional meaning of either "I like the suit you have led," or "I don't like the suit you have led." In the Granovetter system, your message with a high card is "from the point of view of my hand please continue the suit you led OR don't shift to the usual suit. Conversely, a low card suggests a request to the usual suit.
In addition to the opening lead, signals are given when declarer draws trumps or works on a suit. In those cases, play high-low to suggest values in the higher ranking suit; or play low-high to suggest values in the lower ranking suit. Thus the trump echo in the Granovetter system is not used to show trump count. Indeed, about the only time you would ever give count, playing the Granovetter signals, would be when you can see that partner needs to know your count to determine how long to hold up taking an honour.
Do note that all signals are discretionary, since they can be inadvertent. The fact that you can't help giving a signal with the Granovetter system is perhaps its weakness. Otherwise it is superior to the conventional 1) attitude, 2) count, 3) suit preference system. However, it takes some getting used to and requires careful attention to the spot cards your partner plays.