Strong Diamond

This is the web site for the kindle book about contract bridge bidding systems.

Book Summary:

The Precision Club System is one of the world's most popular and successful bidding systems, particularly among experts.

This book turns Precision upside down, making the one diamond opener the strong hand and the one club the catch all bid. In doing so the system becomes even more powerful and precise.

There's also a myriad of new conventions and bidding principles that bring Precision into the 21st Century.

So why play a Mirror Diamond system rather than Precision Club?  The main advantage of a strong diamond is that the one club opener has room for a negative 1 response leaving other responses to give a positive message.  In Precision the 1 opener doesn't have this luxury meaning that you have to choose between responding on really weak hands or passing out the diamond opener that could be two card, neither of which is particularly pleasing.

So why play a Mirror Diamond rather than a 'natural' biding system like SAYC or Acol?  The main advantage is that we limit our hands to narrow ranges and can tell whether we are in part-score, game or slam from responder's first bid.  This often means we can sign-off at a lower level and make contracts when the opponents are going down.  Also it means that when the hand belongs to us we can play for penalties and when it belongs to the opponents we can compete effectively. We always have a way for opener to show extra values from their rebid onwards.  The narrow range means we can use invitational bids as game forces and explore a slam.  2NT for instance is normally a game force asking for more information.

The system is allowed under the American Contract Bridge League list of conventions and the English Bridge Union's Level 4 rules.


Point Range





Artificial non-forcing, no five card major.  This is the unlikely star of the precision diamond system.  Only when your familiar with all the sequences are it's true strength revealed!




Artificial.  All strong hands are opened one diamond, the only forcing opening bid.  The continuations are comprehensive and deal with intervention in new ways.




These are five card majors but I include artificial two level responses.



No five card or singleton major. This is my favorite at match points but you can choose any range you like.  Again I suggest novel responses and invites.




Non-forcing and artificial.  Five card major pre-empts clubs = five hearts, diamonds = five spades.

There are other options for these bids in the book.




Standard weak twos



55 in the minors or a good minor pre-empt depending on style

For full details of the bidding sequences, bidding theory and principles buy buy the kindle book from amazon - out soon!