# alias: FourthSuitForcing
# button-text: 4th Suit Forcing
# gib-works: true
# bba-works: true
# auction-filter: Note...:Fourth.suit
# curate: kind=bidding
# convention-card-ns: 21GF-SPECIALS
# convention-card-ew: 21GF-GIB

/*@chat
--- Fourth Suit Forcing
After 1!C, 1!D, or 1!H, a suit response at the 1-level, and a new suit by
opener, the 4th suit is artificial and game forcing.
NOTE: Many have different agreements about the sequence, 1!C - 1!D - 1!H - 1!S.
Some play it as natural and forcing one round.
Some play it as GF and less than 4 spades and use 2!S for GF with 4 spades. Talk to your partner!
https://www.bridgebum.com/fourth_suit_forcing.php
4NT is Roman Keycard Blackwood (1430) with a trump suit agreed, or quantitative (inviting 6NT) in a notrump auction. Keycard responses:
  • 5!C = 1 or 4 keycards
  • 5!D = 0 or 3
  • 5!H = 2 without the trump queen
  • 5!S = 2 with the trump queen
@chat*/

produce 100
dealer north

#include "script/Calm-Opponents"
#include "script/Predict-Opening-1-Bid-North"

###### Define Bidding Sequences #####
# These variables are defined in the imported script
# The number of cards North has in each suit: s, h, d, c
# North's predicted opening suit: oC, oD, oH, oS

nP = hcp(north)
sP = hcp(south)

# Predict South's 1-level response
sS = spades(south)
hS = hearts(south)
dS = diamonds(south)
cS = clubs(south)

# South responds in D, H, or S (Walsh style), or raises C.  longer than C to avoid 2/1

# Predict South's responding suit
rS  =  sP<11 ? sS>3 and sS>hS : sS>3 and sS>hS and sS>=dS and sS>=cS               // avoid 2/1 in minor
rH  = (sP<11 ? hS>3           : hS>3           and hS>=dS and hS>=cS) and not (rS)
rD  = dS>3           and dS>=cS and not (rS or rH)
rC  = cS>4           and cS>4   and not (rS or rH or rD)
rN  = not (rS or rH or rD or rC)

# Define North's possible rebids
nRC = clubs(north)>3
nRD = diamonds(north)>3
nRH = hearts(north)>3
nRS = spades(north)>3
nRN = shape(north,any 4333+any 4432+any 5332)

# Defining North's opening (not NT) & South's non-GF response
CD = oC and rD
CH = oC and rH
CS = oC and rS
CN = oC and rN
CC = oC and rC

DH = oD and rH
DS = oD and rS
DN = oD and rN
DD = oD and not (DH or DS or DN)

HS = nP<11 ? oH and rS and hS<3 : oH and rS and hS<4     // no Jacoby 2N
HN = oH and rN
HH = oH and not (HS or HN)

CDH = CD and nRH
CDS = CD and nRS and not (CDH)
CDN = CD and nRN and not (CDH or CDS)
CDC = CD and c>5 and not (CDH or CDS or CDN)
CDD = CD and d>3 and not (CDH or CDS or CDN or CDC)

CHS = CH and nRS
CHN = CH and nRN and not (CHS)
CHC = CH and c>5 and not (CHS or CHN)
CHD = CH and nRD and not (CHS or CHN or CHC)
CHH = CH and nRH and not (CHS or CHN or CHC or CHD)

CSN = CS and nRN
CSC = CS and c>5 and not (CSN)
CSD = CS and nRD and not (CSN or CSC)
CSH = CS and nRH and not (CSN or CSC or CSD)
CSS = CS and nRS and not (CSN or CSC or CSD or CSH)

CNC = CN and c>5
CND = CN and nRD and not (CNC)
CNH = CN and nRH and not (CNC or CND)
CNS = CN and nRS and not (CNC or CND or CNH)
CNN = CN and nRN and not (CNC or CND or CNH or CNS)

CCD = CC and nRD
CCH = CC and nRH and not (CCD)
CCS = CC and nRS and not (CCD or CCH)
CCN = CC and nRN and not (CCD or CCH or CCS)
CCC = CC and c>5 and not (CCD or CCH or CCS or CCN)

DHS = DH and nRS
DHN = DH and nRN and not (DHS)
DHC = DH and nRC and not (DHS or DHN)
DHD = DH and d>5 and not (DHS or DHC or DHN)
DHH = DH and nRH and not (DHS or DHC or DHN or DHD)

DSN = DS and nRN
DSC = DS and nRC and not (DSN)
DSD = DS and d>5 and not (DSN or DSC)
DSH = DS and nRH and not (DSN or DSC or DSD)
DSS = DS and nRS and not (DSN or DSC or DSD or DSH)

DNC = DN and nRC
DND = DN and d>5 and not (DNC)
DNH = DN and nRH and not (DNC or DND)
DNS = DN and nRS and not (DNC or DND or DNH)
DNN = DN and nRN and not (DNC or DND or DNH or DNS)

HSN = HS and nRN
HSC = HS and nRC and not (HSN)
HSD = HS and nRD and not (HSN or HSC)
HSH = HS and h>5 and not (HSN or HSC or HSD)
HSS = HS and nRS and not (HSN or HSC or HSD or HSH)

HNC = HN and nRC
HND = HN and nRD and not (HNC)
HNH = HN and h>5 and not (HNC or HND)
HNS = HN and nRS and not (HNC or HND or HNH)
HNN = HN and nRN and not (HNC or HND or HNH or HNS)

##### End of Define Bidding Sequences #####

##### Select appropriate 4SF bidding sequences #####
noReverse = (CDH or CDS or CHS or DHS or DHC or DSC or HSC or HSD) and nP>11 and nP<17 // Avoid Jump Shifts
isReverse = (CHD or CSD or CSH or DSH) and nP>16
allSequences = noReverse or isReverse //and not CDH

# South's constraints
sShape = shape(south,any 7xxx+any 6xxx+any 5xxx-any 74xx-any 64xx-any 5332-any 4432-any 4333)
sRange = sP>12 and sP<16   // with 13-15 I got Soloway jumpshifts
sConstraints = sShape and sRange

# North's constraints
nSpades   = (CS or DS or HS) and spades(north)<=3
nHearts   = (CH or DH)       and hearts(north)<=3
nDiamonds = CD               and diamonds(north)<4

nSupport  = nSpades or nHearts or nDiamonds
twoSuits  = shape(north,any 54xx+any 44xx)
nConstraints = nSupport and twoSuits and nP<19

# Now do it
condition
allSequences and nConstraints and sConstraints and calmOpps
#and CHD

# Just for stats...
bal = shape(north,any 5422+any 5332+any 4432)
h3  = h==3 and (CH or DH)
s3  = s==3 and (CS or DS or HS)


action
average "noReverse " 100 * noReverse,
average "CDH       " 100 * CDH,
average "CDS       " 100 * CDS,
average "CHS       " 100 * CHS,
average "DHS       " 100 * DHS,
average "DHC       " 100 * DHC,
average "DSC       " 100 * DSC,
average "HSC       " 100 * HSC,
average "HSD       " 100 * HSD,
average "isReverse " 100 * isReverse,
average "CHD       " 100 * CHD,
average "CSD       " 100 * CSD,
average "CSH       " 100 * CSH,
average "DSH       " 100 * DSH,
average "balanced  " 100 * bal,
average " Heart sup" 100 * (bal and h3),
average " Spade sup" 100 * (bal and s3),
average "unbalanced" 100 * not bal,
average " Heart sup" 100 * (not bal and h3),
average " Spade sup" 100 * (not bal and s3),