"Dual Minors 1C/1D Forcing" Approach

[hylins]

"Dual Minors 1♣/1♦ Forcing (DMF)" approach

 

Among all the opening bids in most of the bidding systems, 1♦ bid is the most ambiguous bid which becomes clear only after the opener’s 2nd bid.

 

As we all know, the Standard system such as 2/1 and SAYC opens 1 level bid over a wide range of 12-21 HCPS.

One might have experienced opening 18-19 HCPS, 4423 with 1♣ and then hearing 3 passes when one's partner holds 4432 and 4 HCPSs.

The Strong 1♣ system is helpful to avoid this awkward situation, but opponents will do preemptive interference

to make the responses to the 1♣ bid difficult at any opportunity they have.

The Polish Club system introduced the 3-way 1♣ bid to greatly reduce effectiveness of an opponent's preemptive interference.

However, the ambiguous 1♦ bid still remains untouched.

 

In this article, the concept of “Dual Minors 1♣/1♦ Forcing” was explored by restructuring both 1♣ and 1♦ bids as a forcing 2-way bid respectively.

They will each show different 4-card Major holdings for the 12-17 HCPS hands, while showing different holdings in number of suits for strong 18+ HCPS Hands.

This “Dual Minors 1♣/1♦ Forcing” approach shall achieve the advantages of

 

1) narrowing the wide opening range of 1 level suit opening in the Standard system to 6 HCPS.

2) further reducing the effectiveness of an opponent's preemptive interference against the Strong 1♣ bid.

3) showing different 4-card Major holdings with both forcing 1♣ and 1♦ bids which have never been attempted before by any other systems.

 

Using this “Dual Minors 1♣/1♦ Forcing” approach,

one would open with 1♣ when holding (1) 12-17 HCPS hand with ONLY ONE 4-card Major, or (2) 18+ hand with 2-suit or Balanced distribution,

and open with 1♦ when holding (1) 12-17 HCPS hand with BOTH 4-card Majors or NO 4-card Major, or (2) 18+ HCPS hand with 1-suit or 3-suit distribution.

Simply speaking, this new Dual Minors 1♣/1♦ Forcing appraoch modifies the Precision system by

(1) making both 1♣ and 1♦ bids forcing bids and

(2) having two opening HCP ranges of 12-17 and 18+ such that the 2/1 system's 1NT bid can be used directly.

 

The underlined responses to 1♣ bid shown below are very natural except the 1♦ response which can be weak with 0-7 or balanced 16+ with no 4-card Major.

Some of the 1♣ opener’s rebids are also shown.

 

(1.1) 1♣-1♦ 0-7, or Balanced 16+ with no 4-card Major

 

1♥ 12-17, 4-card ♥, may have weak 5+ cards ♦

1♠ 12-17, 4-card ♠, may have weak 5+ cards ♦

1NT 18-19, Balanced

2♣ GF 55, or Balanced 23+

2♦ 12-17, Good 5+ cards ♦ and one not-yet-specified 4-card Major

2♥ 18-19, ♥+♠/♦/♣ 55

2♠ 18-19, ♠+minor 55

2NT 20-22, Balanced

3♣ 18-22, minor 55

3♦ 20-22, Major 55

3♥ 20-22, ♥+minor 55

3♠ 20-22, ♠+minor 55

 

(1.2) 1♣-1♥ 8+, 4+ cards ♥

 

1♠ 12-17, 4-card ♠, may have weak 5+ cards ♦

1NT 18-19, Balanced

2♣ GF 55, or Balanced 23+

2♦ 15-17, Good 5+ cards ♦ and 4-card ♠

2♥ 12-14, 4 card ♥

2♠ 18-19, ♠+minor 55

2NT 20-22, Balanced

3♣ 18-19, minor 55

3♦ 20-22, minor 55

3♥ 15-16, 4-card ♥

3♠ 20-22, ♠+minor 55

3NT Splinter-♠, 4-card ♥

4♣ Splinter-♣, 4-card ♥

4♦ Splinter-♦, 4-card ♥

4♥ Good 16-17, 4-card ♥

4NT RKC-♥

 

(1.3) 1♣-1♠ 8+, 4+ cards ♠

 

(1.4) 1♣-1NT 8-10, Balanced with no 4-card Major

 

2♣ GF 55, or Balanced 23+

2♦ 12-17, Good 5+ cards ♦ and one not-yet-specified 4-card Major

2♥ 18-19, ♥+♠/♦/♣ 55

2♠ 18-19, ♠+minor 55

2NT 20-22, Balanced

3♣ 18-19, minor 55

3♦ 20-22, minor 55

3♥ 20-22, ♥+♠/♦/♣ 55

3♠ 20-22, ♠+minor 55

3NT 18-19, Balanced

 

(1.5) 1♣-2♣ 11+, 5+ cards ♣, may have one 4-card Major

 

2♦ 12-17, 5+ cards ♦ and one not-yet-specified 4-card Major

2♥ 12-17, 4 cards ♥

2♠ 12-17, 4 cards ♠

2NT 12-14, Balanced

3♣ 12-14, 3+ cards ♣

3♦ 18-19, ♠+♥ 55

3♥ 18-19, ♥+♦ 55

3♠ 18-19, ♠+♦ 55

3NT 18-19, Balanced

4♣ 15-16, 4 cards ♣, invite

4♦ RKC-♣

4♥ 20+, ♥+♠/♦ 55

4♠ 20+, ♠+♦ 55

4NT 20-22, Balanced

5♣ 16-17, 4 cards ♣

 

(1.6) 1♣-2♦ 11+, 5+ cards ♦, may have one 4-card Major

(1.7) 1♣-2♥ 5-7, 6+ cards ♥

(1.8) 1♣-2♠ 5-7, 6+ cards ♠

(1.9) 1♣-2NT 11-12, Balanced with no 4-card Major

(1.10) 1♣-3NT 13-15, Balanced with no 4-card Major

 

 

The underlined responses to 1♦ bid are very similar to those to 1♣ bid,

while the 1♦ opener’s rebids are quite different.

 

(2.1) 1♦-1♥ 0-7, or Balanced 16+ with no 4-card Major

 

1♠ 12-17, Both Major 44, can be 4450

1NT 12-14, No 4-card Major (2344, 2353, 3325, 3334)

2♣ 18-21, One to-be-declared 5+ card suit (relay to 2♦ or bid ur suit)

2♦ 12-17, One 6+ cards ♦ suit or ♦+♣ 54 (1354, 2254)

2♥ 18-21, Any 4441 (Responder searches for 44 fit starting from Major)

2♠ 22+, One to-be-declared 5+ card suit (relay to 2N or bid ur suit)

2NT 22+, Any 4441 (Responder searches for 44 fit starting from Major)

3♣ 12-17 ♦+♣ 55/65/66

 

(2.2) 1♦-1♠ 8+, at least one 4+ cards unspecified Major

 

1NT 12-14, No 4-card Major (2344, 2353, 3325, 3334)

2♣ 18-21, One to-be-declared 5+ card suit (relay to 2♦ or bid ur suit)

2♦ 12-17, One 6+ cards ♦ suit or ♦+♣ 54 (1354, 2254)

2♥ 12-17, Both Major 44, can be 4450.

2♠ 22+, One to-be-declared 5+ suit (relay to 2N or bid ur suit)

2NT 22+, Any 4441 (Responder searches for 44 fit starting from Major)

3♣ 12-17 ♦+♣ 55/65/66

3♦ 18-21 4441

3♥ 18-21 1444

3♠ 18-21 4144

3NT 18-21 4414

 

(2.3) 1♦-1NT 8-10, Balanced with no 4-card Major

 

2♣ 18-21, One to-be-declared 5+ suit (relay to 2♦)

2♦ 12-17, 5+ cards ♦

2♥ TBD ????

2♠ 22+, One to-be-declared 5+ card suit (relay to 2N)

2NT 22+, Any 4441 (Responder searches for 44 fit starting from Major)

3♣ 12-17, ♦+♣, 55/65/66

3♦ 18-21, 4441

3♥ 18-21, 1444

3♠ 18-21, 4144

3NT 18-21, 4414

 

(2.4) 1♦-2♣ 11+, 5+ cards ♣, may have 4-card Major

 

2♦ 12-17, 5+ cards ♦

2♥ 12-17, Major 44

2♠ 22+, One to-be-declared 5+ card suit (relay to 2N or bid ur suit)

2NT 22+, 4441 (no fit)

3♣ 12-14, 3+ cards ♣

3♦ 18-21, 5+ cards ♦

3♥ 18-21, 5+ cards ♥

3♠ 18-21, 5+ cards ♠

3NT 18-21, 4441 (no fit)

4♣ 15-16, 4 cards ♣, invite

4♦ 18-21, 4414

4♥ 18-21, 1444

4♠ 18-21, 4144

4NT RKC-♣

5♣ 16-17, 4 cards ♣

 

(2.5) 1♦-2♦ 11+, 5+ cards ♦, may have 4-card Major

(2.6) 1♦-2♥ 5-7, 6+ cards ♥

(2.7) 1♦-2♠ 5-7, 6+ cards ♠

(2.8) 1♦-2NT 11-12, Balanced with no 4-card Major

(2.9) 1♦-3NT 13-15, Balanced with no 4-card Major

[nullve]

What are your other opening bids?

[hylins]

What are your other opening bids?

 

 

Just use the bids (1♥ and up) of Precision system or Polish Club system with modified opening HCP range.

 

The new things are in the 1♣ and 1♦ bids.

[nullve]

Then what is your opening with 12-17 hcp and (31)45 shape? (I assume you treat 2245 as balanced.)

[glen]

Then what is your opening with 12-17 hcp and (31)45 shape? (I assume you treat 2245 as balanced.)

 

My guess: "1♦ when holding (1) 12-17 HCPS hand with BOTH 4-card Majors or NO 4-card Major" (however I think you noticed no rebid for it)

 

Edit: New guess: 2♣ is 12-17 with five or longer clubs and no four card major (this has too wide a range)

 

There have been systems where one of the minor openings denies a four card major while the other one promises one or both, yet this approach, both or none, seems new

 

Yesterday we played against a pair where 1♦ was natural and denied a three card major (could have a four card major). They don't alert nor pre-alert their 1♦ opening, just announce that 1♣ could be 0+

[hylins]

Then what is your opening with 12-17 hcp and (31)45 shape? (I assume you treat 2245 as balanced.)

 

I prefer to extend the Precision 2♣ opening bid to cover both 12-17 hcps, (31)45 and 2245 holdings!

[hylins]

My guess: "1♦ when holding (1) 12-17 HCPS hand with BOTH 4-card Majors or NO 4-card Major" (however I think you noticed no rebid for it)

 

Edit: New guess: 2♣ is 12-17 with five or longer clubs and no four card major (this has too wide a range)

 

There have been systems where one of the minor openings denies a four card major while the other one promises one or both, yet this approach, both or none, seems new

 

Yesterday we played against a pair where 1♦ was natural and denied a three card major (could have a four card major). They don't alert nor pre-alert their 1♦ opening, just announce that 1♣ could be 0+

 

 

 

The One or Both Majors approach has 3 cases to be clarified and it will take at least 2 bids to do so in average.

 

The "Dual Minors 1♣/1♦ Forcing" approach was designed to allow only two very different holdings in each of the 1♣ and 1♦ bids.

Therefore, one can easily tell which holding it is with only 1 bid most of the time when the Exclusive method is used.

[nullve]

Using this “Dual Minors 1♣/1♦ Forcing” approach,

one would open with 1♣ when holding (1) 12-17 HCPS hand with ONLY ONE 4-card Major, or (2) 18+ hand with 2-suit or Balanced distribution,

and open with 1♦ when holding (1) 12-17 HCPS hand with BOTH 4-card Majors or NO 4-card Major, or (2) 18+ HCPS hand with 1-suit or 3-suit distribution.

But e.g.

 

(1.1) 1♣-1♦ 0-7, or Balanced 16+ with no 4-card Major

 

1♥ 12-17, 4-card ♥, may have weak 5+ cards ♦

1♠ 12-17, 4-card ♠, may have weak 5+ cards ♦

1NT 18-19, Balanced

2♣ GF 55, or Balanced 23+

2♦ 12-17, Good 5+ cards ♦ and one not-yet-specified 4-card Major

2♥ 18-19, ♥+Any 55

2♠ 18-19, ♠+minor 55

2NT 20-22, Balanced

3♣ 18-22, minor 55

3♦ 20-22, Major 55

3♥ 20-22, ♥+minor 55

3♠ 20-22, ♠+minor 55

so what do you do with 18+ and (5422)/(5431)?

[hylins]

But e.g.

 

 

so what do you do with 18+ and (5422)/(5431)?

 

Treat them like 1-suitor and open 1♦.

[foobar]

"Dual Minors 1♣/1♦ Forcing (DMF)" approach

 

Among all the opening bids in most of the bidding systems, 1♦ bid is the most ambiguous bid which becomes clear only after the opener’s 2nd bid.

...

 

Can you please post an outline of the entire system, including the 1M, 1N, 2m, 2N, etc. openings?

[hylins]

Can you please post an outline of the entire system, including the 1M, 1N, 2m, 2N, etc. openings?

 

 

The opening bids of DMF(Dual Minors Forcing) system can be summarized as:

 

1♣ - (a) 12-17, One and only one 4-card Major suit, or (b) 18+, 2 suitors, or Balanced

 

1♦ - (a) 12-17, None or both 4-card Major suits, or (b) 18+, 3 suitors, or 1 suitor

 

1♥ - 12-17, 5+ ♥ suit

1♠ - 12-17, 5+ ♠ suit

 

1NT - 15-17

 

2♣ - 12-17, one 5-card ♣ suit plus any 2nd 4-card suit, or one 6+ cards ♣ suit.

 

2♦ - 7-11, 6+ card suits in one of the Majors (if Multi is not allowed, then 6+ card ♦)

2♥ - 7-11, 55 in ♥ and any 2nd suit (if Multi is not allowed, then 6+ card ♥)

2♠ - 7-11, 55 in ♠ and a minor suit (if Multi is not allowed, then 6+ card ♠)

2NT - 7-11, 55 in minors

 

3NT - gambling, no side stopper

 

4♣ - NAMYATS

4♦ - NAMYATS

 

3♣/3♦/3♥/3♠/4♥/4♠ - Preempt

[nullve]

What are Opener's rebids over 1♣-1♠?

[hylins]

What are Opener's rebids over 1♣-1♠?

 

Opener's rebids over 1♣-1♠ is very simliar to Opener's rebids over 1♣-1♥.

 

 

(1.3) 1♣-1♠ 8+, 4+ cards ♠

 

1NT 12-17, 4-card ♥, may have weak 5-card ♦

2♣ GF 55, or Balanced 23+

2♦ 15-17, Good 5+ cards ♦ and 4-card ♥

2♥ 18-19, ♥+minor 55

2♠ 12-14, 4-card ♠

2NT 20-22, Balanced

3♣ 18-19, minor 55

3♦ 20-22, minor 55

3♥ 20-22, ♥+minor 55

3♠ 15-16, 4-card ♠

3NT 18-19, Balanced

4♣ Splinter-♣, 4-card ♠

4♦ Splinter-♦, 4-card ♠

4♥ Splinter-♥, 4-card ♠

4♠ Good 16-17, 4-card ♠

4NT RKC-♠

[awm]

The other openings basically look like Polish Club. So your redistribution of the minor suit openings changes it from:

 

1♣ = 12-14 balanced or 18+ any

1♦ = 12-17 natural

 

to

 

1♣ = 12-17 one four-card major or 18+ balanced/two-suited

1♦ = 12-17 zero or two four-card majors or 18+ one/three-suited

 

The problem I see is that bidding over these multi-way bids in competition can get pretty ugly. Polish club solves it by noting that 1♣ is usually 12-14 balanced, and making a non-forcing (negative) free bid in competition is pretty safe opposite this hand type. This lets responder bid a five-card suit (NF) on many hands that are worth game over the strong option. At first glance that doesn't seem so true here -- I guess if you are always willing to defend when opponents bid opener's four-card major you might be a bit better off, but this seems really dangerous. For example say you hear 1♣-(2♥) and responder has a 5233 hand with something like 8-10 points. You sort of want to make a non-forcing 2♠ bid (this will be great if opener has a weak notrump, very helpful if opener has 18+, and it's also likely to catch partner with four-card spades in which case you could have game), but if you hit a 1444 or 1453 hand this may not work out particularly well. This is less of a problem in Polish club where you are quite safe to bid 2♠ opposite the 1♣ opening (balanced or strong) and you can probably afford to pass opposite the 1♦ opening (partner will reopen with a maximum in any case).

 

Including 15-17 with diamonds also creates some ambiguity in reopening sequences, for example in Polish club after 1♦-(2♠)-Pass-Pass you can double and partner knows diamonds are your primary suit and you have probably 15-17, whereas in the dual minors system could have an 18+ hand (in which case diamonds might not be your suit). Similarly after 1♣-(2[sp)-Pass-Pass you can double and partner knows you have 18+ (again not necessarily the case here where you might want to double with a 1444 15-17 hand).

 

BTW I'm not sure how a 2♣ opening showing 5+♣ and 12-17 is at all playable; most play a tighter range (like 12-15) and many pairs prefer it to guarantee 6+♣ as well.

[PrecisionL]

Are you familiar with MoTown Minors?

 

Maybe some different ideas?

 

Adam's comments are worthy of your consideration. :)

 

https://www.bridgeba...__1#entry789808

[Kungsgeten]

If I understand correctly, these are your actual 12-17 definitions of 1♣ and 1♦:

 

1♣ = a) 12-14 NT with one four card major. b) 12-17 with 5+♦ and one four card major. c) 12-17, 4441 or 5440 with short major.

1♦ = a) 12-14 NT without major, or 4-4 majors. b) 12-17 unbalanced with 5+♦, no major. c) 12-17, 4441 or 5440 with short minor.

 

With unbalanced shape and 5+♣ you open 2♣, with 5+M you open 1M, and with 15-17 NT you open 1NT. I think it can be hard (at least in competition) to know if opener has the NT hand or the diamonds hand, but this is true for strong club with nebulous diamond too. I'm not sure how much gain this will have vs Polish club, but it might be helpful to divide strong hands into different bids. I personally haven't found it to be a problem having all my 12-14 NT hands in 1♣.

[nullve]

What do you open with 12-17 hcp and 4414 shape? (1♦, I guess, but then I have a question for you.)

 

Or 12-17 hcp and 4405 shape? (1♦ or 2♣?)

[hylins]

The other openings basically look like Polish Club. So your redistribution of the minor suit openings changes it from:

 

1♣ = 12-14 balanced or 18+ any

1♦ = 12-17 natural

 

to

 

1♣ = 12-17 one four-card major or 18+ balanced/two-suited

1♦ = 12-17 zero or two four-card majors or 18+ one/three-suited

 

The problem I see is that bidding over these multi-way bids in competition can get pretty ugly. Polish club solves it by noting that 1♣ is usually 12-14 balanced, and making a non-forcing (negative) free bid in competition is pretty safe opposite this hand type. This lets responder bid a five-card suit (NF) on many hands that are worth game over the strong option. At first glance that doesn't seem so true here -- I guess if you are always willing to defend when opponents bid opener's four-card major you might be a bit better off, but this seems really dangerous. For example say you hear 1♣-(2♥) and responder has a 5233 hand with something like 8-10 points. You sort of want to make a non-forcing 2♠ bid (this will be great if opener has a weak notrump, very helpful if opener has 18+, and it's also likely to catch partner with four-card spades in which case you could have game), but if you hit a 1444 or 1453 hand this may not work out particularly well. This is less of a problem in Polish club where you are quite safe to bid 2♠ opposite the 1♣ opening (balanced or strong) and you can probably afford to pass opposite the 1♦ opening (partner will reopen with a maximum in any case).

 

Including 15-17 with diamonds also creates some ambiguity in reopening sequences, for example in Polish club after 1♦-(2♠)-Pass-Pass you can double and partner knows diamonds are your primary suit and you have probably 15-17, whereas in the dual minors system could have an 18+ hand (in which case diamonds might not be your suit). Similarly after 1♣-(2[sp)-Pass-Pass you can double and partner knows you have 18+ (again not necessarily the case here where you might want to double with a 1444 15-17 hand).

 

BTW I'm not sure how a 2♣ opening showing 5+♣ and 12-17 is at all playable; most play a tighter range (like 12-15) and many pairs prefer it to guarantee 6+♣ as well.

 

In order to make the opp's preempt less effective and difficult, DMF(Dual Minors Forcing) approach borrowed Polish club's 3-way 1♣ concept.

However, the 1♣ bid of DMF approach was structured very differently from Polish club's 1♣ bid.

Together with its newly introduced forcing 1♦ twin bid, DMF could solve most if not all of the problems that Polish Polish 1♣ bid encountered.

 

To answer your question about the rebids after one opp's specific preempt,

allow me to do it in a different way, a more general way.

 

Let us try one high level preempt example of 1♣-(3♥)-Pass-Pass-??.

After the strong Polish 1♣ bid, opp preempts with 3♥ and then 2 passes follow. What will the Polish 1♣ opener bid now?

Besides T/O X or Penalty X, one of the following 4 possible holdings (Balanced, 1 suitor, 2 suitor, 3 suitor, before even counting the many different suit combinations) is what the opener wants to communicate to his partner. How will this be accomplished when the available bids are very limited? It is a Mission Impossible!

This same problem also occurs in most of the other systems (Strong Club, Standard, 2/1, ...).

 

In the DMF approach, the strong 1♣ bid of Polish Club system or other systems has been designed into the combo of (a)strong 1♣ bid and (b)strong 1♦ bid.

 

In the case of strong 1♣ bid (Balanced or 2 suitor), the rebids can be as simple and clearly as

 

Pass If you wish

X Penalty (most likely when having good ♥ suit and balanced hand)

3♠ ♠+minor 55 (NF, 18-22, for example)

3N Balanced (23+ ?)

4♣ minors 55 (NF, 18-22 ?)

4♦ minors 55 (GF, 23+ ?)

4♥ TBD (To Be Defined)

4♠ ♠+minor 55 (GF, 23+ ?)

 

For the case of strong 1♦ bid (1 suitor or 3 suitor), the rebids can now become

 

Pass If you wish

X Penalty (most likely when one of your 3-suit is ♥ suit)

3♠ One suitor (relays to 3N, or partner bid his own suit?)

3N To play if you wish

4♣ 4144 (NF, 18-22, for example)

4♦ 4144 (GF, 23+, ?)

4♥ TBD

4♠ TBD

 

As illustrated in the example above, it is very clear that DMF's 1♣ and 1♦ twin bids can do much better than Polish Club's strong 1 ♣ bid after opp's preempt bid.

I believe this advanatage can be extended to the case of (1) 12-17 holding and (2) opp's lower level preempt.

 

By the way, the 1♣ bid in Polish Club system is a 3-way heavily loaded bid. In other words, it has too many possible meanings.

 

(1) 12–14 HCP, no 5-card Major, no 4-card ♦ suit.

(2) 15–17 HCP, 5-card ♣, unbalanced distribution.

(3) 18+ HCP, any distribution.

 

In addition to the normal Strong Club's holding (3), the Polish 1♣ bid includes holdings (1) and (2) to make the opp's preempt less effective and difficult.

However, when opps does preempt especially with a high level bid, the Polish 1♣ opener has a big problem to clarify which of the many possible strong holdings he has.

 

DMF approach was developed by structuring most of those many possible holdings in (1) (2) (3) into two twin bids, 1♣ and 1♦, to help solve the holding clarifing problems with or without opp's preempt!

[hylins]

If I understand correctly, these are your actual 12-17 definitions of 1♣ and 1♦:

 

1♣ = a) 12-14 NT with one four card major. b) 12-17 with 5+♦ and one four card major. c) 12-17, 4441 or 5440 with short major.

1♦ = a) 12-14 NT without major, or 4-4 majors. b) 12-17 unbalanced with 5+♦, no major. c) 12-17, 4441 or 5440 with short minor.

 

With unbalanced shape and 5+♣ you open 2♣, with 5+M you open 1M, and with 15-17 NT you open 1NT. I think it can be hard (at least in competition) to know if opener has the NT hand or the diamonds hand, but this is true for strong club with nebulous diamond too. I'm not sure how much gain this will have vs Polish club, but it might be helpful to divide strong hands into different bids. I personally haven't found it to be a problem having all my 12-14 NT hands in 1♣.

 

At 12-17, the 1♣ and 1♦ bids of DMF(Dual Minor Forcing) approach focus on the 4-card Major holding and pay no attention to the number of minor.

 

1♣ can be 4324, 4351, 4360 (at least 2-card ♦)

1♦ can be 4414, 4450 (at least 1-card ♦)

[hylins]

What do you open with 12-17 hcp and 4414 shape? (1♦, I guess, but then I have a question for you.)

 

Or 12-17 hcp and 4405 shape? (1♦ or 2♣?)

 

2♣ is much simple and clear as 1♦ is a very busy bid.

[nullve]

It looks like the 1♣,...,2♣ openings can more or less be obtained from classic Precision's 1♣,...,2♦ and 2N openings by first shifting ranges upwards by one (if BAL) or two (if unBAL) points so that

 

1♣ = 18+ any

1♦ = 12-14 BAL OR 12-17, unbalanced with either 5+ D, 4D5C, 4D(441) or (41)35

1M = 12-17, 5+ M

1N = 15-17 BAL

2♣ = 12-17, either 6+ C or 5C4M

2♦ = 12-17, "4415 minus 1 card"

 

and then moving

 

* all 4M3-OM hands from 1♦ to 1♣

* all 2245/(31)45 hands from 1♦ to 2♣

* all 4414 hands from 2♦ to 1♦

* all 4405 hands from 2♦ to 2♣

* all (BAL) hands from 2N to 1♣

* all strong (18+) hands that are neither balanced nor 2-suited with at least 5-5 from 1♣ to 1♦.

Edited April 5, 2021 by nullve