# alias: TwoWayFinesse
# button-text: Two-Way Finesse
# gib-works: true
# bba-works: true
# auction-filter: Auction.....\n1[NSH]
# curate: kind=avoidance oracle=shape
# curate-note: This is a pure two-way guess for the QD, not an avoidance/
#   safe-hand board, so there is no danger-suit geometry to verify. Curation
#   should TIER by readability: prefer boards where SOME inference points one
#   way for the Q — an opponent's bid showing length/strength, a revealing
#   opening lead, or skewed vacant places (one defender already marked with
#   more of the other suits). De-prioritise boards with no information (a true
#   50/50), which teach guessing rather than reading.
# convention-card-ns: Basic-Bridge
# convention-card-ew: Basic-Bridge

/*@chat
--- Two-Way Finesse for the Queen of Diamonds
South opens a 5+-card major (1!H or 1!S), the partnership reaches a major game
or 3NT, and South declares.

Teaching feature: declarer's diamond suit is AJx in South opposite KTx in
North — missing only the Queen. The finesse can be taken EITHER way:
• Lead low from dummy toward South's AJ, finesse the J. Wins if East has the Q.
• Lead low from South toward dummy's KT, finesse the T. Wins if West has the Q.

The challenge is deciding which way to commit.

Things to think about:
• Did the auction give either defender a chance to show shape or strength?
• What did the opening lead suggest about distribution?
• Watch early tricks for count signals or revealed lengths.
• Vacant places: if one defender has shown more of the other suits, the Q is
  more likely with the other defender.
• With no information at all, it's 50/50 — pick a side and commit.

Reference: https://www.bridgebum.com/two_way_finesse.php
@chat*/

dealer south

# ----- Diamond holding -----
# South: exactly 3 diamonds = A, J, and one small (no Q, no K, no T)
# North: exactly 3 diamonds = K, T, and one small (no Q)
# Q is guaranteed in opps, randomly placed between East and West.
sDiamondsAJ = hascard(south, AD) and hascard(south, JD)
sDiamondsNoQK = not hascard(south, QD) and not hascard(south, KD) and not hascard(south, TD)
sDiamonds = sDiamondsAJ and sDiamondsNoQK and diamonds(south) == 3

nDiamondsKT = hascard(north, KD) and hascard(north, TD)
nDiamondsNoQ = not hascard(north, QD)
nDiamonds = nDiamondsKT and nDiamondsNoQ and diamonds(north) == 3

# ----- Path 1: South opens 1S -----
p1Shape = spades(south) > 4 and hearts(south) < 5
p1N     = spades(north) > 2
path1   = p1Shape and p1N

# ----- Path 2: South opens 1H -----
p2Shape = hearts(south) > 4 and spades(south) < 5
p2N     = hearts(north) > 2
path2   = p2Shape and p2N

# ----- Common requirements -----
sHcp     = hcp(south) > 13 and hcp(south) < 18
nHcp     = hcp(north) > 7 and hcp(north) < 12
sNoClub5 = clubs(south) < 5
nNoClub5 = clubs(north) < 5

# ----- Combine -----
sDiamonds and nDiamonds and (path1 or path2) and sHcp and nHcp and sNoClub5 and nNoClub5

action
average "Path 1: 1S opener  " 100 * path1,
average "Path 2: 1H opener  " 100 * path2,
average "Q-D with East      " 100 * hascard(east, QD),
average "Q-D with West      " 100 * hascard(west, QD),
average "South HCP avg      "       hcp(south),
average "North HCP avg      "       hcp(north),