Source: Quora

The true advantages of Precision are:

1. The ability to open lighter with safety. Experience has shown that opening 10-12 HCP hands achieves better scores than passing them (almost no top experts are sound openers any more).

2. Less complexity for a given level of bidding accuracy. Think of a bidding system as having two aggregate numeric ratings:

accuracy (0-100) complexity (0-100)

Somebody who plays old fashioned 4-card majors with few conventions has low complexity, let’s say 10, but they achieve limited accuracy, let’s say 40. As a result they will guess in many slam auctions and in competitive auctions. To do better, they must add agreements. As they do, system accuracy goes up, but of course complexity goes up too. Unfortunately, complexity goes up faster than bidding accuracy. Each new agreement added only comes up 1 out 100 hands, so adds little to the aggregate accuracy of the entire system. So in this natural structure, you must add lots of special agreements to get that accuracy up into the 80+ range.

However, serious bridge players are willing to accept high complexity. Let’s say you want to achieve a system accuracy rating of 90. Using Precision, you might get to that accuracy 90 with a complexity of 60. Using 2/1 get to accuracy of 90, you have so many special agreements that complexity will also be 90. (My numbers are not realistic—they are made up to illustrate my point).

1. Precision is more accurate than simple systems because it is more complex. However, any system that is more complex will be more accurate than a simple system.

2. Precision is more complexity-efficient than a natural system. You can achieve more accuracy for a given level of complexity because you need fewer special case agreements than you do in a natural system.

Pros in order of magnitude:

1M-4M: Often when partner opens 1M since he’s limited you can just bid 4M. This is a big win as the opponents don’t know anything during the play.

2club suit opening: When this comes up it’s usually pretty good for you. In fact, it’s arguably good enough to play even without a strong 1club suit opening (i.e. forgo a strong opening entirely), though I prefer the weak 2club suit.

1club suitauctions: slightly better but only slightly and only if you have real discussion especially about what to do after interference. Just playing “a strong 1C opening” with no followup discussion will give you very bad results on these hand types.

Competitive bidding after 1M opening: hand strength is better known, so as with 1M-4M you can bid high quickly even with a pretty decent hand.


1Diamond Suit opening: good opponents will bid aggressively against this. You need good agreements about how to handle interference. You also need some agreements to even make it work in the first place.

Memory load: not just 1club suit but also 1Diamond Suit. The biggest memory load is going to be over interference, and these are the hardest to internalize as there are many different possibilities (and interference systems) and each individual one won’t come up very frequently.

As some background, I grew up playing “standard american” (family gatherings since I was about 8), learned 2/1 in grad school and played it for about a dozen years (and still do with some partners), and decided to play precision with my main partner about 8 years ago.

Some benefits and drawbacks of precision are rare and theoretical, and others are frequent and important. I’m going to start with the frequent and important ones, and trail off somewhere down the line (avoiding the “gee, has that happened in the past 3 years” type).

1. The main advantage, and the main reason we play the system, is that it allows us to be aggressive with light openings. Our style is to open ALL 11-point hands and many 10-point hands. (Well, almost all. I’ll occasionally pass with QJxx Qxx QJx QJx.) In “standard” systems, opening with light values is dangerous because the forcing opening is 22+ points. As responder with a random 6 or 7 count, facing a partner who might have 21 points for their 1-level suit opening, I must bid something — and now we almost always end at the two level, and occasionally the three level. If my partner can have random 10-11 count, that can be too high, especially if there’s no fit. With precision, opener is limited to 15. I can comfortably pass with those misfit hands as responder and stay out of trouble.

2. A corollary to #1 is that responder can jump to game (1M – 4M) with a huge range of hands — essentially zero to about 13 or 14 points. This gives the opponents a big problem. When the bidding goes 1S-P-4S to you and you hold a nice 15 count with hearts, what do you do? Well, that depends on what responder can have. Against standard opponents, you can usually act. With a 13 count, or even a big fitting 10 count, responder cannot raise to 4H: there might be a slam opposite a 20-21 count opener. The raise to 4H is almost always pre-emptive, because with a good hand responder will make a more constructive bid. With your strong NT opener, you figure your can set 4S, or have good hope of making a heart contract. Against precision opponents, you can run into a buzz saw: 12 points opposite 13 points, with 4S cold and 5 of anything your way down a bunch, usually doubled by responder. I can’t count the number of times we’ve scored -100 or -200 vs. a cold , 450, 620 or 650 the other way because of this… or a very nice +500, +800 or +1100 when they didn’t take us seriously.

3. Opponents (especially good ones) will compete aggressively against your strong opening and your poorly-defined 1D opening. This is an important drawback, and it’s critical to have discussions and agreements about the most common special defenses: Mathe and transfer overcalls. Whatever your methods, try to double them whenever you can, especially over 1C when responder is relatively weak — some people will interfere with total crap just to test you, or because they think that’s what you have to do against precision.

There are many more impacts, but these are the most important. If you decide to try precision, I would give it at least 6 months of weekly play — it takes a while to get the kinks out. In my experience it works best if your style is to bid aggressively; if your style is sound openings, it probably isn’t a good fit (although it can be beneficial to learn the ins and outs of the system in order to better defend against it).

Answer Number 4: Mark Hangartnerplayer
I agree with the other answers that the 1Diamond Suit opener is a problem. But I think there are other potential problems.


  • 1Diamond Suit opener can cover quite a range of hands from a balanced 11 count (too weak to open 1NT) to a distributional 15 count, often with longer clubs than diamonds. As a bid it is quite vulnerable to a weak jump overcall in a major.
  • 1NT 12–15 is too wide a range. Other systems have a 3 point range typically 15–17, 16–18, or 12–14.
  • 2club suitis not the greatest positive, yes it may often be preemptive but hard to handle when opener could have relatively weak clubs and a good 4 card major.
  • 1club suit is vulnerable to aggressive overcalls, especially where players use X to show any positive eg 1club suit 1Spade SuitX (=8+ points) 3Spade Suit
  • Rebids after 1Diamond Suitare often ill defined, eg after 1Diamond Suit 1Heart Suitdoes 1Spade Suitshow an unbalanced hand, does 1NT show a specific point count eg 11–12, does 2club suitshow any hand with both Diamond Suit and club suit (maybe 4–4, maybe 4–5, maybe 6–4).


  • very easy sequences to slams in an uncontested auction starting with 1club suit and a positive.
  • easy sequences after 1Heart Suitor 1Spade Suit when there is a fit. (as noted above, these can be preemptive and give away little information).
  • The ability to stay low with a strong hand opposite a bust, and a limited opener in a misfit.

 Answer Number 5: Bob Solick

Bridge (card game): What are the pros and cons of playing Precision versus other bidding systems?

Precision is effective against players who have not studied or played the system. New players tend to do better with Precision than with standard or 2/1, because both members of a pair have read the same book.

Those more familiar with forcing club systems find them much easier to defend against, since the additional definition provided on limited [not-one-club] hands pinpoints opener’s strength and distribution so closely that his hand can be counted out early in the play. Critics emphasize the weakness of the ill-defined one diamond opening. They are correct.

The one club opening bid is also a big minus, maybe the biggest. Natural opening bids in the minors make standard or two-over-one methods far more accurate on the little hands, which occur more often than big ones.

The light opening tendency by Precision players is an advantage, but not fully realized because they do not have the machinery to distinguish between balanced hands and distributional hands.

A well-constructed natural system can easily open much lighter [legal minimum for agreements is 8 HCP] on highly distributional hands and still control the outcome, as long as the players are willing to use sound openings on balanced hands and four card majors opposite a passed hand. The complexity/accuracy trade off is far more favorable to four card systems than five. The opposite conclusion is possibly attributable to lack of familiarity with 4CM.

 Answer Number 6: Helene Hoegsbro Thygesen,

Compared to natural systems with a strong artificial 2club suitopening (SA, SEF, Acol, 2/1 etc),

Precision tends to win when:

      • you don’t have the patience to study a lot of bidding theory, so a wide -ranging standard opening (11–21 points or so) would leave partner guessing how strong you are, and in many situations you wouldn’t know if partner’s bid is forcing or not. Strong club systems are easier for beginners.
      • you have (10)11–15 points. Knowing that you don’t have 16+ makes partner make better decisions, especially when opps interfere, and it allows you to rebid aggressively with good shape without showing points which you don’t have
      • in particular, 11–15 points with 6 clubs is great as you can preempt with a 2club suitopening
      • with 16+ you tend to win when opps don’t interfere as partner can establish a game force with just 8 points.
      • with 16+ you will occasionally win even if opps interfere, as partner can always enter the auction with 8 points and often with 5. In particular, with a balanced 18-count it is nice that you don’t have to bid again if the opps interfere and partner is broke.

Precision tends to lose when:

      • Opps interfere over your 1club suitopening. Good openents will overcall very light so you will get some difficult contested auctions where the SA bidders are left in peace as opps have to little to overcall over a natural opening (especially if your suit is spades so a natural opening would have prevented a 1-level overcall)
      • You have a 4414 hand or 4M+5clubs with 11–15 points. Whichever agreement you have made, it would have been more convenient to be able to open a natural 1club suit.
      • You have a strong 2- or 3-suited hand with primarily diamonds, and partner responds 1Diamond Suitto your 1club suitopening. Also 4414 and hands with 5 clubs are awkward. Unless you allow 4-card major rebids or have some other non-standard solution.

So who should play Precision? I think Precision is good if

      • You are a beginner and play in a timid field where opps won’t overcall very aggressively. Precision is easier to learn and also quite effective as long as opps don’t overcall aggresively over your 1cl opening.
      • You are a system geek. “Natural” systems are poorly designed because the distinction between the minor suit opening don’t mean much. So basically any reasonably thought-through system will be an improvement. It doesn’t have to be Precision, of course. Strong club systems are particularly effective when you are a geek and opps don’t interfere over your 1cl opening, as you can start using slam conventions already from the 1Sp rebid (1club suit-1Heart Suit-1Spade Suit, here 1Spade Suit is a relay)

OTOH, Precision is maybe not good for you if you play at a medium level (say stronger club nights or small, open tournaments) and you are not a system geek. You will need to find a way to counter opps’ aggressive overcalls, and that requires a lot of work.

Most strong club players have no idea of the strong part of their system.

The good points of a strong club:

The limited 1-Major openings.

Natural, limited 2-minor openings. (Provided that they deny a major; otherwise, you’re losing to every standard pair in the room)

I think the Precision 1Diamond Suitis roughly neutral. What you get from defining range well you lose from defining shape badly. Lots of system work might make it a small winner.

The big loser is the strong club. Lack of shape definition will often put you a round of bidding behind the room, which can hurt in a lot of ways (particularly if the opponents bid, as good ones often will). Lots of system work, particularly on dealing with competitition, might bring the strong club to neutral.

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