LEADING TRUMPS TO PREVENT A RUFF
When it is apparent that one adversary can “ruff” a suit, or when a “cross-ruff” is imminent, it is important that you guard against such a contingency by at least two rounds of trumps. Of course, if you hold the commanding trump, this presents no difficulties; but, when the winning trump is with the adversary, you should try to tempt him to hold it up second in hand by refraining from a high card lead. For instance, with queen and seven of trumps in one hand and king jack ten nine eight in the other, lead the seven instead of the queen.
If your trumps are in sequence you can often obtain two rounds by leading the lowest of your sequence rather than the highest card.