user:lazcatluc:2-under

2-under general description

1♣ is strong (usually 14+ in the first 2 seats, 17+ in 3rd and 4th)
1nt is weak in the first two seats 10-13; 3rd and 4th seats 14-16
all the bids from 1♦ to 4♦ (except for 1♥, 1nt, 2♥ and 3♥) are 2-under, showing the n+2 suit, unbalanced hands and denying unbid 4+ card major(s); intermediate range (8-13 usually in the first 2 seats) - in 3rd and 4th seats the HCP range can vary from 0 to 16
- the n+1 response is always a relay asking for description
  - n response = minimum hand
  - anything else = natural, maximum hand
- 2nt, if available = 4 card fit, inv+
- new suit = non-forcing (strong hands bid n+1 first)
a double by responder is not negative, but proposing a penalty
- new suit: 10 cards in the two suits bid or singleton in the doubled suit
- normally should accept the penalty proposal
a reopening double shows a singleton in the opponents’ suit (so a penalty pass is also allowed, in addition to the penalty proposing double)
handy conventions that fit nicely: rubens, various forms of lebensohl, fit jumps; we don’t play SWITCH in this system
signals: UDCA; discarding: UDCA; priorities always: Count/Attitude/Suit Preference; we give Count often
leads: always 2/4; top of sequence; J from KJT

1!C Opening

1♣ = 14+ (17+)
- 1♦ = 0-9 hcp any
  - 1♥ = 18+
    - 1♠ = 0-5 any (but not with ♠)
      - 1nt = 18-21
      - 2♣ = any GF
        
        2♦ = no suit worth mentioning (KJxxx and QJTxx are worth mentioning)
        
        2nt = 24+
        
        stayman + transfers apply
      - 2nt = 22-23
    - 1NT = 0-5 hcp, 5+♠
    - 2♣ = 6-9, balanced
    - 2♦, 2♥, 2♠, 3♣ = nat 6-9 hcp
    - 2nt = never used
  - 1♠, 1NT, 2♣, 2♦, 2♥ = nat, 14-17
    - normal structures apply (fit bids after 1♠ and stayman+transfers after 1nt)
- 1♥, 1♠, 2♣, 2♦ = 10+, nat
- 1nt = 10-13
- 2♥, 2♠, 3♣, 3♦ = weak, constructive, 6-9 hcp
- 2nt = 14+

1!D Opening

1♦ = 4♠ exactly
- 1♥ = relay (denies fit)
  - 1♠ = 8-10 hcp
  - other, natural, maximum
- 1♠ = to play, 3♠
- new suit non-forcing (use relay for strong hands)
- 2nt = inv+ 4♠s

1!H Opening

1♥ = 4♥ exactly
1♥ - 2♥ = 4♥, weak
1♥ - 2nt = 4♥, inv+
minor rebids show 5+ cards in the minor
1♥ - 1♠ = 5+ cards, forcing 1 round
1♥ - 1nt = relay, forcing
- 2♣/2♦ = 5 cards, nat
- 2♥ = 4441, singleton ♠
- 2♠ = 5440, 5♣, ♠ void
- 2nt = 5440, 5♦, ♠ void
- 3♣/3♦ = 6 cards, nat
1♥ - 2♣, 2♦ = nat, non-forcing

1!S Opening

4+ ♣s, usually 54 in the minors
- 1nt = to play
  - opener is allowed to rebid 2!M with a 3 card suit and a nice hand (singleton in the other major)
- 2♣, 2♦ = to play
- 2♥, 2♠ = nat, forcing
- 2nt = bid your best minor (can be strong)
- 3♣/3♦ = weak

2!C Opening

2♣ = 5♥, 8-13 hcp, unbalanced
- 2♦ = relay
  - 2♥ = minimum hand
  - anything else = natural, maximum
- new suit non-forcing (use relay for strong hands)
- 2nt = 4+ card fit, inv+
- fit jumps
- 3nt nat

2♦, 2♠, 2nt, 3♣, 3♦, 3♠, 3nt, 4♣, 4♦ openings have a similar structure

2!H Opening

2♥ = 4-4 / 5-4 majors, 8-13 hcp
- 2nt = relay
  - 3♣ = 4♣s
  - 3♦ = 4♦s
  - 3♥ = 5♥s
  - 3♠ = 5♠s
- 3♣ = inv+, ♥ fit
- 3♦ = inv+, ♠ fit

3!H Opening

3♥ = 5-5 / 6-5 majors, 8-13 hcp
- 4♣ = relay
  - 4♦ = 5-5
  - 4♥, 4♠ = 6 cards

If they X our transfer

pass = to play
xx = relay
2nt = inv+, fit
fit jumps
new suit non-forcing

If they X our 1NT

XX = inv+, 12+ hcp, establishes an unlimited forcing pass sequence; subsequent doubles are for penalty
new suit = non-forcing, 5 cards, partner can raise with 4 cards
pass = non-forcing, denies a 5 card suit; subsequent doubles are for take-out
1nt - [X] - pass - [pass] -
- pass = 4333 shape
- new suit = 5 cards
- XX = 2 4-card suits
  - try to find a 4-4 fit economically