After discussing your defense against a precision 1♦ opener (see Precision's Secret Weapon ), it is time to refine your strategy for interfering with a strong 1♣.

Before bidding, you must understand the effect of your action.  Since one opponent has 16+ points, you will probably end up defending.  Exposing your distribution to opponents playing the same contract as the field can be disastrous.  Similar to overcalling against natural players, you need a reason for entering the auction.

Once again, knowing how to interfere with your opponent's auction requires a better understanding of their methods...

Precision players' most common response structure after an overcall is:

If the interference is 2♥ or lower
P = 0-4 HCP or a penalty pass (waiting for a reopening double)
X = 5-8 HCP (invitational values)
BID = Natural Game Force
Direct Cue-bid = Balanced Game Force without a stopper

After responder doubles to show 5-8

The strong club bidder's new suit is forcing for 1 round.  Here is an example auction:

Playing 2♠/3♣/3♦ as non forcing would force opener to jump and waste valuable bidding space with game forcing hands.

If the interference is 2♠ or higher

P = 0-7 HCP or a penalty pass (waiting for a reopening double)
X = 8+ HCP (game force)
BID = Natural Game Force
Direct Cue-bid = 3 suited take out of  the suit bid

With this information in mind we can develop a plan of attack.  Here is a list of thoughts to help you:

1. The biggest weakness of a strong club is that opener does not introduce their long suit until their second bid.  Taking up as much room as possible immediately applies the maximum pressure. Preempting 2♦ or 2♥ will exploit the system flaw after the 5-8 double shown above.   Higher preempts are even more effective as you might force a pass out of responder with just less than a game force and leave the 1♣ bidder making a judgement call whether to balance.
2. Preempt with stronger than normal hands as well. This increases the frequency you can create difficult problems for your opponents, with a smaller risk of missing a game.
3. While the risk of missing a game is substantially lower, do not completely ignore it.  When they open 1♣ and you overcall, discuss how partner can show a good raise. Play that the cheapest level of NT shows a good raise, since there is no suit to cue-bid.
4. Use 1 level overcalls to direct the lead.  If your opponents have game or slam and partner ends up on lead, don't miss the opportunity to help partner.  This is especially prudent after the auction starts 1♣ P 1♦.  Any time the opponent is planning on bidding some number of NT, getting a lead director in may win you the board.
5. Discuss if your conventional methods over 1♣ also apply after 1♣ P 1♦.

Style of defense varies a lot depending on your opponents methods.  For example when playing against a pair that plays an elaborate relay system, it becomes even more effective to interfere.  Breaking up their normal relays typically eliminates their systemic advantages.  The advice in this article series is based on a typical precision system, remember to adjust based on your opponents actual methods.

More defense against precision to come.