The 5-3-1 DP system

Before you read this, you may want to familiarize yourself with the previous related article on short suit distribution points.

Let's say you are applying the 3-2-1 system for short suit distribution points. If you have read the previous article, you will know that applying points for short suits is a way of saying that "by having a short (non trump) suit, you make ruffing easier in that suit - therefore, you potentially make the opponent's high cards in that suit partially useless".

If you are void, for example, you apply 3 points. By applying 3 points, you are saying that on average, you benefit the equivalent of a K. For example, your opponents may have a AK, but your partner has a Qx (which is vulnerable to the opponents), but you are void. So your average benefit is 7HCP - 2HCP = 5, provided you have sufficient trumps to ruff the enemy (if you don't, you further discount the benefit).

In the cases of competitive bidding, your partnership may have bid one suit, and the opponents another. It is very likely that your partnership is short in the opponent's suit. Not only that, but the chances of your being able to deny your opponents the full use of their suit (if the trump contract is yours), is much higher. Intuitively, you want to assign more points to your void or singleton in the opponent's bidded suit.

This is where the 5-3-1 system comes in. When bidding in a competitive situation, and you know or highly suspect (from the bidding) that opponents have a long combined suit that you are short in, instead of applying 3,2,1 points for void, singleton, doubleton, you apply 5,3,1 instead.

Note that 5-3-1 is merely an average. When opponents very clearly show a strong strong fit in a suit, you should consider revising this to visualize what high cards in opponents suit you can defeat if you had the contract. 

Consider this hand. Your partner has overcalled 2H (say your agreement says 11+HCP and 5+ cds). You inquire with your opponents about 4S and is told that it is preemptive (probably 5 spades and <10 HCP). Your void indicates that it is likely partner only has a likely 3 spades (since opps have 10).

What would I bid?

You have 11HCP and a void in spades.  What DP do you assign your spade void? If you assign 5, that brings your total to 16. That is very close to the 29 you need to be reasonably sure of 5H.

While it is possible that your partner has good honors in spades (e.g. KQx), it seems unlikely with opponents having 10 spades between them. I would bid 5H - my void is worth more than 5 pts and partner may have more an a minimum.

Note: a secondary consideration is that you have 6 losers in your hand. Losing Trick Count (LTC)  hand valuation (as a backup evaluation) would suggest 5H is a good risk provided your partner didn't go wild with his overcall 8-). You may look up LTC yourself.