Add late surrender support and rename soft table

- Add late_surrender config option with EV calculation (-0.5)
- Generate 1,152 strategy files (576 sur + 576 nosur)
- Add surrender (R) action with purple color in legend
- Rename "Soft Totals" to "Soft Hands" for accuracy
- Run MC simulation for all surrender configs

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: hankhsu1996

docs/usage.md

@@ -114,7 +114,7 @@ Columns: Dealer's upcard (2-A)
 
 A "hard" hand has no ace counted as 11, or would bust if the ace were 11.
 
-### Soft Totals
+### Soft Hands
 
 Rows: Player's soft hand (A2-A9)
 Columns: Dealer's upcard (2-A)

scripts/generate_strategies.py

@@ -19,7 +19,8 @@ def config_to_filename(config: GameConfig) -> str:
     msh = f"sp{config.max_split_hands}"  # sp2, sp3, sp4
     peek = "peek" if config.dealer_peeks else "nopeek"
     bj = "32" if config.blackjack_pays == 1.5 else "65"
-    return f"{decks}-{s17}-{das}-{rsa}-{msh}-{peek}-{bj}.json"
+    sur = "sur" if config.late_surrender else "nosur"
+    return f"{decks}-{s17}-{das}-{rsa}-{msh}-{peek}-{bj}-{sur}.json"
 
 
 def get_table_data(tables: StrategyTables) -> dict:
@@ -53,7 +54,7 @@ def generate_for_base_config(base_params: tuple) -> list[dict]:
     Strategy tables are the same for both payouts and max_split_hands,
     only house edge differs.
     """
-    decks, h17, das, rsa, peek = base_params
+    decks, h17, das, rsa, peek, surrender = base_params
     output_dir = Path("web/public/strategies")
 
     # Create base config for strategy tables (these don't affect strategy)
@@ -65,6 +66,7 @@ def generate_for_base_config(base_params: tuple) -> list[dict]:
         max_split_hands=4,  # Doesn't affect strategy tables
         dealer_peeks=peek,
         blackjack_pays=1.5,  # Doesn't affect strategy tables
+        late_surrender=surrender,
     )
 
     # Generate strategy tables once (same for all payouts and max_split_hands)
@@ -84,6 +86,7 @@ def generate_for_base_config(base_params: tuple) -> list[dict]:
                 max_split_hands=max_hands,
                 dealer_peeks=peek,
                 blackjack_pays=bj_pays,
+                late_surrender=surrender,
             )
 
             filename = config_to_filename(config)
@@ -97,6 +100,7 @@ def generate_for_base_config(base_params: tuple) -> list[dict]:
                     "max_split_hands": config.max_split_hands,
                     "dealer_peeks": config.dealer_peeks,
                     "blackjack_pays": config.blackjack_pays,
+                    "late_surrender": config.late_surrender,
                     "description": str(config),
                 },
                 **table_data,
@@ -132,6 +136,7 @@ def main():
             bool_options,  # double_after_split
             bool_options,  # resplit_aces
             bool_options,  # dealer_peeks
+            bool_options,  # late_surrender
         )
     )
 

src/blackjack/config.py

@@ -15,9 +15,7 @@ class GameConfig:
         max_split_hands: Maximum hands from splitting (2-4, default 4)
         blackjack_pays: Payout ratio for blackjack (1.5 for 3:2, 1.2 for 6:5)
         dealer_peeks: True if dealer peeks for blackjack with 10/A showing
-
-    Note:
-        Surrender is not modeled.
+        late_surrender: True if late surrender is allowed (after dealer peeks)
     """
 
     num_decks: int = 6
@@ -27,6 +25,7 @@ class GameConfig:
     max_split_hands: int = 4  # Can resplit up to 4 hands
     blackjack_pays: float = 1.5  # 3:2
     dealer_peeks: bool = True
+    late_surrender: bool = False
 
     @classmethod
     def default(cls) -> "GameConfig":

src/blackjack/evaluator.py

@@ -194,6 +194,9 @@ def get_all_evs(
         if can_split and len(player_cards) == 2 and player_cards[0] == player_cards[1]:
             evs["split"] = self.ev_split(player_cards[0], dealer_upcard)
 
+        if self.config.late_surrender and len(player_cards) == 2:
+            evs["surrender"] = -0.5
+
         return evs
 
     def _get_all_evs_composition(
@@ -233,6 +236,9 @@ def _get_all_evs_composition(
                 player_cards[0], dealer_upcard, adj_probs, adj_dealer_outcomes, removed
             )
 
+        if self.config.late_surrender and len(player_cards) == 2:
+            evs["surrender"] = -0.5
+
         return evs
 
     def _get_dealer_outcomes_adjusted(

src/blackjack/renderers.py

@@ -21,5 +21,5 @@ class StrategyData:
     soft_table: TableData
     pair_table: TableData
     legend: str = field(
-        default="S=Stand, H=Hit, Dh=Double/Hit, Ds=Double/Stand, P=Split"
+        default="S=Stand, H=Hit, Dh=Double/Hit, Ds=Double/Stand, P=Split, R=Surrender"
     )

src/blackjack/strategy.py

@@ -11,6 +11,7 @@
 ACTION_DOUBLE_OR_STAND = "Ds"  # Double if allowed, otherwise stand
 ACTION_SPLIT = "P"
 ACTION_SPLIT_OR_HIT = "Ph"  # Split if DAS, otherwise hit
+ACTION_SURRENDER = "R"  # Surrender (give up half bet)
 
 
 class BasicStrategy:
@@ -36,7 +37,7 @@ def get_action(
             can_double: Whether doubling is allowed
 
         Returns:
-            Action code (S, H, D, Dh, Ds, P)
+            Action code (S, H, D, Dh, Ds, P, R)
         """
         evs = self.ev_calc.get_all_evs(
             player_cards, dealer_upcard, can_split, can_double
@@ -58,6 +59,9 @@ def get_action(
         if best_action == "split":
             return ACTION_SPLIT
 
+        if best_action == "surrender":
+            return ACTION_SURRENDER
+
         if best_action == "stand":
             return ACTION_STAND
 

src/blackjack/tables.py

@@ -38,7 +38,7 @@ def get_strategy_data(self) -> StrategyData:
                 rows=self._build_hard_rows(hard),
             ),
             soft_table=TableData(
-                title="Soft Totals",
+                title="Soft Hands",
                 headers=self.DEALER_HEADERS,
                 rows=self._build_soft_rows(soft),
             ),