There are lots of different systems; they all have advantages and disadvantages. Choose the one you think has the least disadvantages and which you think you will remember best
Revolving
A simple system that is fairly easy to remember
Think of the suits in a circle Clubs Diamonds Hearts Spades Clubs.
A low discard asks for the suit directly below, a low club indicating Spades; a high discard asks for the suit directly above
(a high Spade signaling Clubs). In a suit contract, the trump suit is ignored. It is generally accepted that fives and sixes are negative
McEnney
The first discard is a suit preference. It says you do not want the suit discarded so your card tells partner which of the
two remaining suits you prefer. A high card for the higher ranking of the remaining suits and a low card for the lower ranking.
Again fives and sixes are usually thought to be showing no preference.
Dodds
The first discard shows the following:: an odd card indicates an interest in the other suit of the same colour.
An even card shows interest in the suit discarded.
Odd or Even
With this system, the first discard shows the following: if it is an odd card it is encouraging in that suit;
if it is a low even card it is a suit preference signal for the lower ranking suit of the other two suits;
if it is a high even spot card it shows preference for the higher ranking suit.
Natural Discards
A high card in a suit says you want that suit.
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A low card says that you have no interest in that suit
The major problem with natural discards is that discarding
a high card can be detrimental to your holding in that suit. For this reason some people play Reverse Natural Discards
where the opposite applies.
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