A system of honour leads against a no- trump contract whereby the lead of a king or 10 suggests a strong holding, and the lead of an ace, queen or jack suggests a relatively weak holding.
Ace from: A K x
King from: A K Q, A K J, A K 10, K Q J, K Q 10
Queen from: K Q x, K Q 9, Q J 10
Jack from: J 10 x
Ten from: A J 10, A 10 9, K J 10, K 10 9, Q 10 9
Nine from: 10 9 x