A system of discards whereby the rank of the discard signals for a lead in another suit. A discard of a high card asks for the lead of the suit ranking immediately above the suit of the discard (clubs above spades) and similarly for a low ranking discard (spades below clubs).
West leads the ♥3 against South’s 3NT. East plays the queen, taken by South’s ace. When declarer plays diamonds, West holds up his ace until the third round to allow his partner the chance to signal. Playing ‘revolving discards’, on the third round of diamonds the ♠3 or the ♣10 will ask for a heart.