Exceptions to Defensive Principles

Cover an honour with an honour.
Second hand play low, third hand play high.
These are generally good defensive principles, however there are situations where they are not appropriate to apply.

What is the purpose of covering an honour led by declarer, either from their hand or dummy? It is to promote a trick, or tricks, in your or partner’s hands. Where this is not possible then the cover should not be applied. Take this scenario.

Dummy         Q, J, 10, 9, 8
You               K, 7, 6,

There is no point in covering if there is a lead from dummy as you cannot set up a trick for your side. Your best hope is to play small and hope that declarer has A, x. Also if declarer is leading from Q, J, x, x it is probably best to wait for the second honour to be led before covering.
The other situation where not to cover is where you can’t lose your honour, for example where you can see A, x in dummy or suspect that declarer only has A, x.
The principle is if you can’t see the possibility of setting up a trick(s) for you or partner, do not cover.

In general second hand play low, third hand play high is good advice. However again there are situations where this should be ignored. Take this scenario.

Dummy      A, J, 10, 9, 8      Declarer ?,?, (?)
You            K, 7

Declarer has no other entry to Dummy and leads small from their hand. If you play low declarer finesses the 8 for partners Q to win. When declarer regains the lead and subsequently leads towards dummy they are going to take the rest of the tricks in that suit. If however you cover the first lead with the K declarer can take the Ace, but partner can hold up taking the Q to the appropriate time, restricting Declarer to two tricks at the most. If Declarer ducks the K, partner with the Q can still control the run of the suit. Even if your holding is
K, x, x it is still best to cover to give best chances for holding declarer to one or two tricks. However if your holding is K, x, x, x then it is best not to cover as your partner may hold Q singleton or doubleton, in which case they will win any finesse and you can control the run of the suit.

Generally third hand will play high, but carefully consider what the outcome of this may be. For example say partner leads a low card and dummy shows up with Q, J, !0, 9. You hold K 3 small. If you cover dummy’s card with the K and declarer wins with the Ace they have three more tricks in the suit. Your best hope is that Declarer has Ace singleton or doubleton and so your K can live to fight another day.

Happy Bridging.