This is a complete detailed bridge bidding system using 1C as a strong and forcing bid with most hands 16+ pts unbalanced or 17+ pts balanced. The system employs transfer responses over 1C. Included is a ACBL convention card. For complete system see my blog.
Looking for someone to learn this Precision system to play on bridgebase.com
There is an obvious defense to Bergen, which allows opponents to enter the bidding, when they normally wouldn't have the values to.
3C (if 7-9 or 6-9): Double = takeout double of the major. Don't so much need hcp as distribution as they are unlikely to be able to play in 3CX. Might find any easy sacrifice or get to play it, especially if opener cant bid game.
3D (If limit): Double is for lead
If people are playing Reverse Bergen you do the other way round. 3C-X: lead, 3D-X: takeout
1M-3M : use this as a mixed raise (Bergen style) 7-9 4 card support
1M-2N: standard forcing raise plus 4-card limit raises. You have to change your responses to what your would do over 1M-X-2N (Dormer). Of course, you could use more complicated methods, there are many methods for 2N as a limit+ raise available on the internet or in books.
Pre-emptive raises: just pass, raise to 2M or 4M depending on your playing strength.
Using this method you don't give away easy doubles of artificial bids
Thanks to John Montgomery's Revision Precision for showing the error of my ways.
I've experimented with using 1D as the strong forcing bid in a Precision based system. Here is link to STR 1D convention card The idea is that 1C is better as your nebulous bid than 1D. Then putting 1D as your strong bid which is one step higher, the theory is you often get interference and on those hands it doesn't matter whether you opened 1C or 1D.
To get 1C as promising 2+ clubs you would have to open 2D with 5D4M, which I don't think is a good idea. The other option is to open 1M with 4M and 5 or 6D and 2D with a 6+D 1-suiter, which is better but I really like 5-card majors. So I have chosen to make 1C potentially 0C and make it F1 with 1D as a negative or some better hand hands that don't fit into the responding system. 2C is a standard Precision 2C but promises 6+. 2D is an intermediate bid which promises 6+D and denies a 4+ major. Also, 2H/2S are weak 2's. 2N shows both minors 8-12 hcp.
So your strong bid is 1D is artificial 0+D F1, 17+ hcp unbalanced or 18+ hcp balanced
and 1C is: - 11-14 NV 12-14 Balanced 2+C 12-16 unbalanced 0+C - 5C possibly with a 4+ card side - 5+D with a 4+ card side, only 5-card major if a maximum and 6+D - poor 6+ C/D suit (that isn't good enough for a 2C/2D opening) - 13-16 minor 2-suiter - 7-card semi-solid minors with a side A/K