[Dr Abc]

Minor Suit Forcing is a bridge bidding system designed for advanced bridge players.
It is the key that both 1♣ and 1♦ openings are forcing bids. While 1♣ opening has a broad HCP range, 1♦ opening shows a hand with 15+ HCP and without 5 card major.

1 Opening Bids

1♣:

11-12 HCP, 4 card major (not 4333 shape for 11 HCP) or 5+ minor suit including 5332 shape
13-14 HCP, 4 card major or balanced or 5 card minor of 5332 shape
15-16 HCP, 5+ major suit or 4 card major, either 5+ minor suit or 4441 shape
17+ HCP, 5+ major suit
25+ HCP, balanced or no 4 card major, 5+ minor suit

1♦:

15-17 HCP, no 4 card major, 5+ minor suit including 5332 shape
18-20 HCP, no 5 card major
21-22 HCP, no 5 card major, either 4441 shape or 5+ minor suit including 5332 shape
23-24 HCP, no 5 card malor
25+ HCP, 4 card major, either 4441 shape or 5+ minor suit

1♥:

11-14 HCP, 5+ ♥ suit, ♥ is longer than ♠ suit

1♠:

11-14 HCP, 5+ ♠ suit, ♠ is not shorter than ♥ suit

1N:

15-17 HCP, balanced hand (i.e., 4333 or 4432 shape)

2♣:

13-14 HCP, no 4 card major, no 5 card ♦, 5+ ♣ suit, not 5332 shape

2♦:

13-14 HCP, no 4 card major, 5+ ♦ suit, not 5332 shape

2♥:

8-10 HCP, 6+ ♥ suit with 1+ honor card (i.e., A, K or Q)

2♠:

8-10 HCP, 6+ ♠ suit with 1+ honor card

2N:

21-22 HCP, balanced hand

3♣:

8-10 HCP, no 4 card major, 7+ ♣ suit with 1+ honor card

3♦:

8-10 HCP, no 4 card major, 7+ ♦ suit with 1+ honor card

3♥:

8-10 HCP, 7+ ♥ suit with 1+ honor card

3♠:

8-10 HCP, 7+ ♠ suit with 1+ honor card

3N:

13-14 HCP, 8+ minor suit with 2+ honor cards, 9 winning tricks

4♣:

8-10 HCP, no 4 card major, 8+ ♣ suit with 1+ honor card

4♦:

8-10 HCP, no 4 card major, 8+ ♦ suit with 1+ honor card

4♥:

8-10 HCP, 8+ ♥ suit with 2+ honor cards

4♠:

8-10 HCP, 8+ ♠ suit with 2+ honor cards

4N:

13-14 HCP, 6+ ♦ cards, 6+ ♣ cards, 10 winning tricks

5♣:

8-10 HCP, no 4 card major, 9+ ♣ suit with 2+ honor cards

5♦:

8-10 HCP, no 4 card major, 9+ ♦ suit with 2+ honor cards

2 After 1♣ Opening

1♣-1♦:

0-8 HCP, any
9-12 HCP, no 5 card major

1♣-1♥:

9+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-1♠:

9+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-1N:

13+ HCP, no 5 card major

2.1 After 1♦ Response

1♣-1♦-Pass:

11-12 HCP, no 4 card major, 5+ ♦ suit

1♣-1♦-1♥:

11-14 HCP, 4 ♥ cards
15-16 HCP, 4+ ♥ cards, unbalanced
17 HCP, 5+ ♥ suit

1♣-1♦-1♠:

11-14 HCP, 4 ♠ cards, no 4 ♥ cards
15-16 HCP, 4+ ♠ cards, unbalanced
17 HCP, 5+ ♠ suit

1♣-1♦-1N:

13-14 HCP, no 4 card major, balanced or 5 minor suit of 5332 shape

1♣-1♦-2♣:

11-12 HCP, no 4 card major, 5+ ♣ suit

1♣-1♦-2♦:

21-24 HCP, 5+ major suit

1♣-1♦-2♦-2♥:

0-1 HCP, less than 3 ♥ cards or 4333 shape
2-3 HCP, less than 3 ♥ cards

1♣-1♦-2♦-2♠:

0-1 HCP, 3+ ♥ cards, less than 3 ♠ cards, not 4333 shape
2-3 HCP, 3+ ♥ cards, less than 3 ♠ cards

1♣-1♦-2♦-2N:

0-1 HCP, 3+ ♥ cards, 3+ ♠ cards, not 4333 shape
2-3 HCP, 3+ ♥ cards, 3+ ♠ cards

1♣-1♦-2♦-3♣:

4-12 HCP, less than ♥ cards or less than 3 ♠ cards

1♣-1♦-2♦-3♦:

4-12 HCP, 3+ ♥ cards, 3+ ♠ cards

1♣-1♦-2♦-3♥:

4-12 HCP, 5+ ♥ cards, less than 3 ♠ cards

1♣-1♦-2♦-3♠:

4-12 HCP, 5+ ♠ cards, less than 3 ♥ cards

1♣-1♦-2♥:

18-20 HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-1♦-2♠:

18-20 HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-1♦-2N:

25+ HCP, balanced

1♣-1♦-3♣:

25+ HCP, no 4 card major, 5+ ♣ suit

1♣-1♦-3♦:

25+ HCP, no 4 card major, 5+ ♦ suit

1♣-1♦-3♥:

25+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-1♦-3♠:

25+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

2.2 After 1♥ Response

1♣-1♥-1♠:

11-14 HCP, no 3 ♥ cards, 4 ♠ cards
15-17 HCP, no 3 ♥ cards, 5+ ♠ cards

1♣-1♥-1N:

13-14 HCP, no 3 ♥ cards, no 4 ♠ cards, balanced or 5 minor suit of 5332 shape

1♣-1♥-2♣:

11-12 HCP, no 3 ♥ cards, no 4 ♠ cards, 5+ ♣ suit

1♣-1♥-2♦:

11-12 HCP, no 3 ♥ cards, no 4 ♠ cards, 5+ ♦ suit

1♣-1♥-2♥:

11-13 HCP, counting the hand shape 11-13 points, 3 or 4 ♥ support

1♣-1♥-2♠:

18-20 HCP, 5+ ♠ suit (may have 3+ ♥ support)
21+ HCP, no 3 card ♥, 5+ ♠ suit

1♣-1♥-2N:

15-16 HCP, no 3 card ♥, 4 ♠ cards, unbalanced shape

1♣-1♥-3♣:

15-17 HCP, 3+ ♥ support, less than 3 ♣ cards

1♣-1♥-3♦:

15-17 HCP, 3+ ♥ support, less than 3 ♦ cards

1♣-1♥-3♥:

12-14 HCP, counting the hand shape 14-15 points, 3 or 4 ♥ support

1♣-1♥-3♠:

15-17 HCP, 3+ ♥ support, less than 3 ♠ cards

1♣-1♥-3N:

25+ HCP, no 3 ♥, balanced

1♣-1♥-4♣:

18-20 HCP, 5+ ♥ support, direct asking for Roman keys
21+ HCP, 3+ ♥ support
25+ HCP, no 3 ♥, no 4 ♥ cards, 5+ ♣ suit

1♣-1♥-4♦:

25+ HCP, no 3 ♥, no 4 ♥ cards, 5+ ♦ suit

1♣-1♥-4♥:

13-14 HCP, counting the hand shape 16+ points, 3 or 4 ♥ support

2.3 After 1♠ Response

1♣-1♠-1N:

11-12 HCP, no 3 ♠ cards, 4 ♥ cards
13-14 HCP, no 3 ♠ cards, balanced or 5 minor of 5332 shape

1♣-1♠-2♣:

11-12 HCP, no 3 ♠ cards, no 4 ♥ cards, 5+ ♣ suit

1♣-1♠-2♦:

11-12 HCP, no 3 ♠ cards, no 4 ♥ cards, 5+ ♦ suit

1♣-1♠-2♥:

15-17 HCP, 5+ ♥ suit, no 3 ♠ support
18-20 HCP, 5+ ♥ suit (may have 3+ ♠ support)
21+ HCP, 5+ ♥ suit, no 3 ♠ support

1♣-1♠-2♠:

11-13 HCP, counting the hand shape 11-13 points, 3 or 4 ♠ support

1♣-1♠-2N:

15-16 HCP, no 3 card ♠, 4 ♥ cards, unbalanced shape

1♣-1♠-3♣:

15-17 HCP, 3+ ♠ support, less than 3 ♣ cards

1♣-1♠-3♦:

15-17 HCP, 3+ ♠ support, less than 3 ♦ cards

1♣-1♠-3♥:

15-17 HCP, 3+ ♠ support, less than 3 ♥ cards

1♣-1♠-3♠:

12-14 HCP, counting the hand shape 14-15 points, 3 or 4 ♠ support

1♣-1♠-3N:

25+ HCP, no 3 ♠ cards, balanced

1♣-1♠-4♣:

18-20 HCP, 5+ ♠ support, direct asking for Roman keys
21+ HCP, 3+ ♠ support
25+ HCP, no 3 ♠, no 4 ♥, 5+ ♣ suit

1♣-1♠-4♦:

25+ HCP, no 3 ♠, no 4 ♥, 5+ ♦ suit

1♣-1♠-4♠:

13-14 HCP, counting the hand shape 16+ points, 3 or 4 ♠ support

2.4 After 1N Response

1♣-1N-2♣:

11-12 HCP, no 5 card major, 4+ ♣ cards (may have 4 card major)

1♣-1N-2♦:

11-12 HCP, no 5 card major, 4+ ♦ cards (may have 4 card major)

1♣-1N-2♥:

11 HCP, 4 ♥ cards, 4 ♠ cards, 4432/4441 shape
12 HCP, 4 ♥ cards, 4333 shape or 4 ♠ cards, 4432/4441 shape
13-14 HCP, 4 ♥ cards
15-16 HCP, 4+ ♥ cards, unbalanced
17 HCP, 5+ ♥ suit

1♣-1N-2♠:

12 HCP, 4 ♠ cards, 4333 shape
13-14 HCP, 4 ♠ cards, no 4 [12 HCP, 4 ♥ cards 4333 shape
15-16 HCP, 4+ ♠ cards, unbalanced
17 HCP, 5+ ♠ suit

1♣-1N-2N:

13-14 HCP, no 4 card major, balanced or 5 minor suit of 5332 shape

1♣-1N-3♣:

15-16 HCP, 4 card major, 4+ ♣ cards

1♣-1N-3♦:

15-16 HCP, 4 card major, 4+ ♦ cards

1♣-1N-3♥:

18+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-1N-3♠:

18+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-1N-3N:

25+ HCP, no 4 card major, balanced

1♣-1N-4♣:

25+ HCP, no 4 card major, 5+ ♣ suit

1♣-1N-4♦:

25+ HCP, no 4 card major, 5+ ♦ suit

2.5 Responses After Opponent Double

1♣-Db-Pass:

0-8 HCP, weak hand

1♣-Db-1♦:

9-12 HCP, no 5 card major, 5+ ♦ suit

1♣-Db-1♥:

9-12 HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-Db-1♠:

9-12 HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-Db-1N:

9-10 HCP, no 4 card major, balanced

1♣-Db-2♣:

13+ HCP, no 5 card major, 4+ ♣ suit, unbalanced (may have 4 card major)

1♣-Db-2♦:

13+ HCP, no 5 card major, 4+ ♦ suit, unbalanced (may have 4 card major)

1♣-Db-2♥:

13+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-Db-2♠:

13+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-Db-2N:

13+ HCP, balanced

1♣-Db-Rd:

9-10 HCP, 4 card major or unbalanced
11-12 HCP, no 5 card major

2.6 Responses After Opponent 1♦ Overcall

1♣-1♦-Pass:

0-8 HCP, weak hand

1♣-1♦-1♥:

9-12 HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-1♦-1♠:

9-12 HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-1♦-1N:

9-10 HCP, no 4 card major, balanced with ♦ stoppers

1♣-1♦-2♣:

13+ HCP, no 5 card major, 4+ ♣ suit, unbalanced (may have 4 card major)

1♣-1♦-2♦:

13+ HCP, 4 card major or balanced without ♦ stopper

1♣-1♦-2♥:

13+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♣-1♦-2♠:

13+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♣-1♦-2N:

13+ HCP, no 4 card major, balanced with ♦ stoppers or 4+ ♦ cards

1♣-1♦-Db:

9-10 HCP, 4 card major or balanced without ♦ stopper or unbalanced
11-12 HCP, no 5 card major

2.7 Responses After Opponent 1♥ Overcall

1♣-1♥-Pass:

0-8 HCP, weak hand

1♣-1♥-1♠:

9-12 HCP, 5+ ♠ suit

1♣-1♥-1N:

9-10 HCP, no 4 ♠ cards, balanced with ♥ stoppers

1♣-1♥-2♣:

13+ HCP, no 5 ♠ cards, 4+ ♣ suit, unbalanced (may have 4 ♠ cards)

1♣-1♥-2♦:

13+ HCP, no 5 ♠ cards, 4+ ♦ suit, unbalanced (may have 4 ♠ cards)

1♣-1♥-2♥:

13+ HCP, 4 ♠ cards or balanced without ♥ stopper

1♣-1♥-2♠:

13+ HCP, 5+ ♠ suit

1♣-1♥-2N:

13+ HCP, no 4 ♠ cards, balanced with ♥ stoppers or 4+ ♥ cards

1♣-1♥-Db:

9-10 HCP, 4 ♠ cards or balanced without ♥ stopper or unbalanced
11-12 HCP, no 5 ♠ cards

2.8 Responses After Opponent 1♠ Overcall

1♣-1♠-Pass:

0-8 HCP, weak hand

1♣-1♠-1N:

9-10 HCP, no 4 ♥ cards, balanced with ♠ stoppers

1♣-1♠-2♣:

13+ HCP, no 5 ♥ cards, 4+ ♣ suit, unbalanced (may have 4 ♥ cards)

1♣-1♠-2♦:

13+ HCP, no 5 ♥ cards, 4+ ♦ suit, unbalanced (may have 4 ♥ cards)

1♣-1♠-2♥:

11-12 HCP, 5+ ♥ suit

1♣-1♠-2♠:

13+ HCP, 4 ♥ cards or balanced without ♠ stopper

1♣-1♠-2N:

13+ HCP, no 4 ♥ cards, balanced with ♠ stoppers or 4+ ♠ cards

1♣-1♠-3♥:

13+ HCP, 5+ ♥ suit

1♣-1♠-Db:

9-10 HCP, 4+ ♥ suit or balanced without ♠ stopper or unbalanced
11-12 HCP, no 5 ♥ cards

3 After 1♦ Opening

1♦-1♥:

0-6 HCP, any
7-8 HCP, no 5 card major

1♦-1♠:

7+ HCP, 5+ major suit

1♦-1NT:

9+ HCP, no 5 card major

3.1 After 1♥ Response

1♦-1♥-1♠:

17 HCP, 4 card major, 5+ minor suit or 4441 shape
18-22 HCP, no 5 card major, unbalanced

1♦-1♥-1♠-1N:

0-4 HCP, any shape
5 HCP, no 4 card major

1♦-1♥-1♠-2♣:

5 HCP, 4 card major, 3+ ♣ cards
6-7 HCP, no 5 card major, 4+ ♣ cards

1♦-1♥-1♠-2♦:

5 HCP, 4 card major, 3+ ♦ cards
6-7 HCP, no 5 card major, 4+ ♦ cards

1♦-1♥-1♠-2♥:

5-6 HCP, 5+ ♥ suit

1♦-1♥-1♠-2♠:

5-6 HCP, 5+ ♠ suit

1♦-1♥-1♠-2N:

5 HCP, both 4 ♥ and 4 ♠ cards, 4441 shape
6 HCP, both 4 ♥ and 4 ♠ cards, 4432 shape

1♦-1♥-1♠-3♣:

8 HCP, no 4 card major, 4+ ♣ cards

1♦-1♥-1♠-3♦:

8 HCP, no 4 card major, 4+ ♦ cards

1♦-1♥-1♠-3♥:

8 HCP, 4 ♥ cards, no 4 ♠ cards

1♦-1♥-1♠-3♠:

8 HCP, 4 ♠ cards, no 4 ♥ cards

1♦-1♥-1♠-3N:

6 HCP, 4 ♥ and 4 ♠ cards, 4441 shape
7-8 HCP, 4 ♥ and 4 ♠ cards, 4432 or 4441 shape

1♦-1♥-1♠-1N-Pass:

17-19 HCP, no 5 card suit

1♦-1♥-1♠-1N-2♣:

18-20 HCP, no 4 card major, 5+ ♣ suit

1♦-1♥-1♠-1N-2♦:

18-20 HCP, no 4 card major, 5+ ♦ suit

1♦-1♥-1♠-1N-2♥:

20-22 HCP, 4 ♥ cards

1♦-1♥-1♠-1N-2♠:

20-22 HCP, 4 ♠ cards, no 4 ♥ cards

1♦-1♥-1♠-1N-2NT:

21-22 HCP, 5 minor suit of 5332 shape

1♦-1♥-1♠-1N-3♣:

21-22 HCP, no 4 card major, 5+ ♣ suit, not 5332 shape

1♦-1♥-1♠-1N-3♦:

21-22 HCP, no 4 card major, 5+ ♦ suit, not 5332 shape

1♦-1♥-1N:

18-20 HCP, balanced

1♦-1♥-2♣:

15-17 HCP, no 4 card major, 5+ ♣ suit

1♦-1♥-2♦:

15-17 HCP, no 4 card major, 5+ ♦ suit

1♦-1♥-2♥:

23-24 HCP, 4 ♥ cards, 5+ minor suit or 4441 shape

1♦-1♥-2♠:

23-24 HCP, 4 ♠ cards, no 4 ♥ cards, 5+ minor suit or 4441 shape

1♦-1♥-2NT:

23-24 HCP, balanced

1♦-1♥-3♣:

23-24 HCP, no 4 card major, 5+ ♣ suit

1♦-1♥-3♦:

23-24 HCP, no 4 card major, 5+ ♦ suit

1♦-1♥-3♥:

25+ HCP, 4 ♥ cards, 5+ minor suit or 4441 shape

1♦-1♥-3♠:

25+ HCP, 4 ♠ cards, no 4 ♥ cards, 5+ minor suit or 4441 shape

3.2 After 1♠ Response

1♦-1♠-1NT:

17 HCP, 4 card major, unbalanced
18-20 HCP, no 5 card major
21-22 HCP, 4 card major, unbalanced

1♦-1♠-2♣:

15-17 HCP, no 4 card major, 5+ ♣ suit

1♦-1♠-2♦:

15-17 HCP, no 4 card major, 5+ ♦ suit

1♦-1♠-2♥:

23-24 HCP, 4 ♥ cards, 5+ minor suit or 4 ♥ cards, 4441 shape

1♦-1♠-2♠:

23+ HCP, 4 ♠ cards, no 4 ♥ cards, 5+ minor suit or 4441 shape

1♦-1♠-2N:

23-24 HCP, balanced

1♦-1♠-3♣:

23-24 HCP, no 4 card major, 5+ ♣ suit

1♦-1♠-3♦:

23-24 HCP, no 4 card major, 5+ ♦ suit

1♦-1♠-3♥:

25+ HCP, 4 ♥ cards, 5+ minor suit or 4 ♥ cards, 4441 shape

1♦-1♠-3♠:

25+ HCP, 4 ♠ cards, no 4 ♥ cards, 5+ minor suit or 4441 shape

3.3 After 1N Response

1♦-1N-2♣:

15-17 HCP, no 4 card major, 5+ ♣ suit

1♦-1N-2♦:

15-17 HCP, no 4 card major, 5+ ♦ suit

1♦-1N-2♥:

17-20 HCP, 4 ♥ cards

1♦-1N-2♠:

17-20, 4 ♠ cards, no 4 ♥ cards

1♦-1N-2N:

18-20 HCP, no 4 card major

1♦-1N-3♣:

21-24 HCP, no 4 card major, 5+ ♣ suit

1♦-1N-3♦:

21-24 HCP, no 4 card major, 5+ ♦ suit

1♦-1N-3♥:

21+ HCP, 4 ♥ cards

1♦-1N-3♠:

21+ HCP, 4 ♠ cards, no 4 ♥ cards

1♦-1N-3N:

23-24 HCP, no 4 card major, balanced

3.4 Responses After Opponent Double

1♦-Db-Pass:

0-4 HCP, weak hand

1♦-Db-1♥:

5-8 HCP, 5+ ♥ suit, ♥ longer than ♠

1♦-Db-1♠:

5-8 HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♦-Db-1N:

5-6 HCP, no 4 card major, balanced

1♦-Db-2♣:

9+ HCP, no 5 card major, 4+ ♣ suit, unbalanced (may have 4 card major)

1♦-Db-2♦:

9+ HCP, no 5 card major, 4+ ♦ suit, unbalanced (may have 4 card major)

1♦-Db-2♥:

9+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♦-Db-2♠:

9+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♦-Db-2N:

9+ HCP, balanced

1♦-Db-Rd:

5-6 HCP, 4 card major
7-8 HCP, no 5 card major

3.5 Responses After Opponent 1♥ Overcall

1♦-1♥-Pass:

0-4 HCP, weak hand

1♦-1♥-1♠:

5-8 HCP, 5+ ♠ suit

1♦-1♥-1N:

5-6 HCP, no 4 ♠ cards, balanced with ♥ stoppers

1♦-1♥-2♣:

9+ HCP, no 5 ♠ cards, 4+ ♣ suit, unbalanced (may have 4 ♠ cards)

1♦-1♥-2♦:

9+ HCP, no 5 ♠ cards, 4+ ♦ suit, unbalanced (may have 4 ♠ cards)

1♦-1♥-2♥:

9+ HCP, 4 ♠ cards or balanced without ♥ stopper

1♦-1♥-2♠:

9+ HCP, 5+ ♠ suit

1♦-1♥-2N:

9+ HCP, no 4 ♠ cards, balanced with ♥ stoppers

1♦-1♥-Db:

5-6 HCP, 4 ♠ cards
7-8 HCP, no 5 ♠ cards

3.6 Responses After Opponent 1♠ Overcall

1♦-1♠-Pass:

0-4 HCP, weak hand

1♦-1♠-1N:

5-6 HCP, no 4 ♥ cards, balanced with ♠ stoppers

1♦-1♠-2♣:

9+ HCP, no 5 ♥ cards, 4+ ♣ suit, unbalanced (may have 4 ♥ cards)

1♦-1♠-2♦:

9+ HCP, no 5 ♥ cards, 4+ ♦ suit, unbalanced (may have 4 ♥ cards)

1♦-1♠-2♥:

7-8 HCP, 5+ ♥ suit

1♦-1♠-2♠:

9+ HCP, 4 ♥ cards or balanced without ♠ stopper

1♦-1♠-2N:

9+ HCP, no 4 ♥ cards, balanced with ♠ stoppers

1♦-1♠-3♥:

9+ HCP, 5+ ♥ suit

1♦-1♠-Db:

5-6 HCP, 4+ ♥ cards
7-8 HCP, no 5 ♥ cards

3.7 Responses After Opponent 2♣ Overcall

1♦-2♣-Pass:

0-4 HCP, weak hand

1♦-2♣-2♦:

7-8 HCP, no 4 card major, 5+ ♦ suit

1♦-2♣-2♥:

7-8 HCP, 5+ ♥ suit, ♥ longer than ♠

1♦-2♣-2♠:

7-8 HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♦-2♣-2N:

9+ HCP, no 4 card major, balanced with ♣ stoppers

1♦-2♣-3♣:

9+ HCP, 4 card major or balanced without ♣ stopper

1♦-2♣-3♦:

9+ HCP, no 5 card major, 4+ ♦ suit, unbalanced (may have 4 card major)

1♦-2♣-3♥:

9+ HCP, 5+ ♥ suit, ♥ longer than ♠

1♦-2♣-3♠:

9+ HCP, 5+ ♠ suit, ♠ not shorter than ♥

1♦-2♣-Db:

5-6 HCP, 4+ ♥ cards, 4+ ♠ cards
7-8 HCP, no 5 card major

4 After 1♥ Opening

1♥-1♠:

9+ HCP, no 3 ♥ cards, 5+ ♠ suit

1♥-1N:

8 HCP, no 2 ♥ cards, 4+ ♠ cards
9 HCP, no 2 ♥ cards, 4 ♠ cards
10 HCP, no 3 ♥ cards, no 5 ♠ cards
11 HCP, no 3 ♥ cards, no 4 ♠ cards

1♥-2♣:

11 HCP, no 3 ♥ cards, 4+ ♣ cards, 4 ♠ cards
12+ HCP, no 3 ♥ cards, 4+ ♣ cards

1♥-2♦:

11 HCP, no 3 ♥ cards, 4+ ♦ cards, 4 ♠ cards
12+ HCP, no 3 ♥ cards, 4+ ♦ cards

1♥-2♥:

7-11 HCP, counting the hand shape 10-11 points, 3+ ♥ cards

1♥-2♠:

13 HCP, 3+ ♥ cards, void in ♠
14 HCP, 3+ ♥ cards, less tahn 2 ♠
15-18 HCP, 3+ ♥ cards, less than 3 ♠

1♥-2N:

12-13 HCP, 4333 shape

1♥-3♣:

13 HCP, 3+ ♥ cards, void in ♣
14 HCP, 3+ ♥ cards, less tahn 2 ♣
15-18 HCP, 3+ ♥ cards, less than 3 ♣

1♥-3♦:

13 HCP, 3+ ♥ cards, void in ♦
14 HCP, 3+ ♥ cards, less tahn 2 ♦
15-18 HCP, 3+ ♥ cards, less than 3 ♦

1♥-3♥:

9-12 HCP, counting the hand shape 12-13 points, 3+ ♥ cards

1♥-3N:

14-16 HCP, 4333 shape

1♥-4♣:

19+ HCP, 3+ ♥ cards, asking for Roman key cards

1♥-4♦:

17-18 HCP, 4333 shape

1♥-4♥:

9-12 HCP, counting the hand shape 14+ points, 3+ ♥ cards
13-14 HCP, counting the hand shape 15-16 points, 3+ ♥ cards

5 After 1♠ Opening

6 After 1N Opening

7 After 2♣ Opening

-2♥:
9+ HCP, 5+ ♥ suit, ♥ longer than ♠, asking for opener’s 3 ♥ card support

-2♠:
9+ HCP, 5+ ♠ suit, ♠ not shorter than ♥, asking for 3 ♠ card support

8 After 2♦ Opening

9 After 2N Opening

[pescetom]

Non-natural systems have their own forum, maybe someone could move this.
I have no related expertise, but FWIW at first sight 2♣/♦ look underloaded.

[mycroft]

...and done.

I would enjoy playing my strong club defence against 1♦ and my strong NT defence (basically, would be closer to KitW's "grunt defence") against 1♣.

That's without checking the probabilities. I'll probably run up a script to do that, to see if my gut feel is right.

[mycroft]

Okay, I think there are no bugs in my simulator - I no longer have a hand that either has no bids (but is a non-preempt opener) or more than one opening bid. Frankly, with a system like this, I'm quite impressed that there aren't hands that legitimately fit two opening bids; in that it's well-designed.

(Please note, I believe that OP's native language is not English: what OP means by "5+ minor suit but 5332 shape" is "5+m but *not* 5332 shape". Took me a while to work that out. This is not a criticism; when my Italian or Spanish is this good, I get to criticize. Just for others reading.)

Sample output (the categories are in the same order as in the OP, for the 1m openings):

1C:
    HCP11_12: 4656
    HCP13_14: 3366
    HCP15: 269
    STR_M: 1648
    MED_ROMAN: 118
    STR_ROMAN: 7
    HUGE_NT: 8
Total 1C: 10072

1D:
    STR_BAL: 663
    VSTR_BAL: 35
    STR_5MIN332: 818
    STR_UNBAL: 252
    HUGE_5MIN332: 38
    HUGE_UNBAL: 6
Total 1D: 1812

Totals:
1C: 10072  # calculated differently than above, as a doublecheck
1D: 1812   # ditto
1M: 5858
1NT: 2028
2NT: 149
2m: 976
20895 (20895) out of 50000  # again, these two counts should match (if they don't, a hand was uncounted/doublecounted)

So, I feel comfortable with my gut-feeling reactions.

• 40%ish of hands are opened (not bad; conservative, but not bad. Note, this doesn't count preempts);
  
• half of them are opened 1♣; 80+% of those are "weak NT or 11-15 4cM or long minor". That's easily within "We call an opening 1 of a minor bid which may be short but isn't necessarily strong a 'grunt'" for me.
  
• 1♦ is strong (but half the strong hands (the ones with a major) have been "grunt"ed out into 1♣). Our strong club defence will work at least adequately against this, especially since we have a call for "both majors" and we are more likely than a normal "strong club" to have a long major (or a fit, for that matter).
  
• 15% are the great calls of 1M and 1NT. Love that, that's why I play Precision.
  
• 2m openers are 2% ish; as pescetom says, that's probably underutilized. Even if you pushed it to 11-15 (and lumped the 5332 11-12s in with the "don't open flat balanced hands", I guess), you'd probably triple that. You still have two ranges (min, max) and invitations still are okay (again, "min, max") if not NT-precise.

Untangling the various options of 1m, even if we don't get into the auction, seems like a daunting task (and I notice it's the part of the system OP *doesn't* present responses or first-round rebids for). But I've played Polish and Swedish Clubs before, I know this kind of thing is resolvable. However, having a "go-to expected hand" when the opponents *do* overcall, like Swedish Club's "weak/kamikaze NT" or Polish's "weak NT. Sure, it might be clubs, but opener often is able to show that later" (or, similarly, Precision 1♦'s "assume the flat hand that can't open 1NT") really helps. This one is more amorphous; I'm sure the OP knows what "to expect", but it's not clear to me yet.

Having said all that, the idea that responder passes 1M unless there's a possibility of game (or a M fit) went out of fashion with the Precision community before 1990. Bidding immediately, rather than beginning to compete only after the opponents have passed information is worth so much more than opener knowing that "the right max should bid game". In fact, I love opening 1M and 90% of the time leaving it in partner's hands to place the contract or ask questions.

I would love to see some results with this system.

For me, there aren't advantages over 21st century Precision (of any stripe, including 0+1♦ and 2m being 11-15, 6m or 5m-4M) that are worth the even more (or maybe it's just new-to-me, not more. But it is new-to-me) difficulty untangling 5- and 6-way minors. Oh, and describing them to the opponents in a 10-second PreAlert.

(and if the OP is JL, who I talked to a lot in Saskatoon, uh, you know, you have in fact solved most of these issues. I still don't have 15 years to work it out like you and P have).

Edit as my response on responses to 1m have been added, I've struck out the parenthetical. I haven't looked at the responses to see how resistant they are to fourth-hand (or even second hand) competition.

[DavidKok]

The system strongly reminds me of a strong diamond structure. The strong diamond systems I'm familiar with have approximately the following system overview:

• 1♣: Catchall, nebulous, by far the most frequent of all the opening bids.
  
• 1♦: Strong, usually 17+ or 16+ or so, nebulous.
  
• 1M: 5(+), limited, usually 11-16 or so.
  
• 1NT: A NT range, either Kamikaze or Strong, with the other hand type opening 1♣.
  
• 2m: 5(+), limited, usually 11-16 or so. Trades with 1♣ to solve problem hands. A common style is to deny a 4cM.

This is very similar to a Precision club with 1♣ and 1♦ swapped and all the ranges filed down a little to adjust for the different amount of bidding space.
All the strong diamond systems I've seen struggle with four problems:

• Using 1♦ as a strong bid is somewhat too high, and the constructive bidding over the strong opening is really very difficult compared to strong club.
  
• The nebulous 1♣ folds like a wet paper bag in competition. It's arguably too overloaded for constructive bidding already, and when the opponents interfere it's a crapshoot. What's more, it contains some of the weakest hands in the system (and is therefore among the most likely to see interference) and is by far the most frequent opening bid (and is therefore the most important part of the bidding system).
  
• The natural 2m openings as I wrote them aren't actually assets, the range is slightly uncomfortably wide (especially of 2♦).
  
• Disclosing which hands are contained in the nebulous 1♣ is difficult, and I've had the unfortunate pleasure of playing against opponents who were sneaking in definitions. But even the people who are up front about this have difficulty with proper disclosure, as there's so many different hand types in there.

Your system takes a lot of the strong hands of 1♦ and the awkward hands of 2m and puts them in 1♣ as well. This helps resolve problems 1+3 but greatly exacerbates numbers 2 and 4. Personally I find problem number 2 to be the biggest issue of strong diamond systems, and I think somewhere between 25% and 50% of all effort on a system like this should go into competitive agreements after we open 1♣. In your system, with the exceptionally high strain on 1♣, probably more.
There's another point about your constructive system over 1♣: normally strong diamond systems 'flip the minors compared to Precision' precisely to allocate more space to their more common opening bid, hoping to gain more resolution using e.g. transfer-based responses or cheap forcing asking bids. Your system over 1♣ has some similarities with standard Precision structures, but I think on the points where it deviates it's a downgrade. I expect that you will respond 1♦ to 1♣ very very often as it contains all weaker-than-game-forcing hands without a 5cM, and now you've used a full round of bidding space to share little information about either hand. This is, again, very vulnerable to interference.

I understand that this is a system you've already put a lot of energy and passion into, and I think it is really nice to develop more unorthodox systems. At the same time I worry about certain design choices, such as 1♣-1♦ being not forcing, 1♣-1M showing a five card suit, all weak hands having to pass your 1M openings, but mostly the lack of competitive agreements. Sorry for being so blunt, but I think this system is unplayable against real opponents - the competitive auctions will cost a lot.

[mikeh]

I strongly agree with David. The annals of bridge bidding theory abound with home-grown methods that work well on paper but don’t work well against opps alive to the inevitable inherent flaws. Designing a system is time consuming….and I can only imagine how many hours the OP put into this. It’s an impressive structure…if one assumes that the opps will remain silent most of the time. I know, from having designed my less elaborate 4 Card major forcing club system with weird two bids some 40 years ago, how invested one can become in one’s ideas, and I commend the OP for his efforts.

I’m not saying don’t play it. I am saying that the OP and his partner need to really work hard on overcoming preemption, which in this case could be as simple as a 1S overcall. Ideally one would want to get close to how Meckwell, in their day, handled interference over their forcing 1C…I read, many years ago, that analysis of their high level matches showed that they did better, on average, after interference than they did without it! And they were VERY good without it.

[straube]

The use of 1♣ and 1♦ in this system places too much emphasis on describing opener’s hand, while significantly limiting responder’s ability to show his own hand. The clearest evidence of this imbalance is that responder cannot bid beyond 2♦ on his first turn. Even if the system were later revised to allow constructive responses at the two-level (such as 2♥ or higher), the current limitations underscore the problem.

I've made similar criticisms of Polish Club along the same lines: both 1C structures don't empower responder because it isn't clear whether opener has a good hand or not...frequently not even after his first rebid.

While this version does improve on traditional strong diamond systems by reducing the burden on the 1♦ opening, it introduces a new problem: the artificial, non-passable 1♣ opening imposes strain on the entire response structure, particularly the 1♦ response. 1C-P is a very useful response to have!

[foobar]

In addition to the excellent suggestions already made, one way to salvage this system might to move all 16+ to 1♣, include the min balanced to 1♦ along with the minor canape hands with the 4CM and 44441s. Of course, only 1♣ is forcing, but it's guaranteed to be strong and is much more resilient to interference (as is 1♦.

And with those two changes, it almost replicates to world class Nystrom-Upmark system while preserving all your investments.

[straube]

 foobar, on 2025-July-27, 23:35, said:

In addition to the excellent suggestions already made, one way to salvage this system might to move all 16+ to 1♣, include the min balanced to 1♦ along with the minor canape hands with the 4CM and 44441s. Of course, only 1♣ is forcing, but it's guaranteed to be strong and is much more resilient to interference (as is 1♦.

And with those two changes, it almost replicates to world class Nystrom-Upmark system while preserving all your investments.

That would take away what it offers as new. Its core is having two forcing 1m openings.

[foobar]

 straube, on 2025-July-28, 08:40, said:

That would take away what it offers as new. Its core is having two forcing 1m openings.

The way to look at it might be that OP almost came up with a world class system in isolation. Based on feedback, it was tweaked to make it truly world class.