diff --git a/variants.py b/variants.py
index 087b5bc..a200a95 100644
--- a/variants.py
+++ b/variants.py
@@ -50,6 +50,24 @@ class Suit:
 
         self.colors = colors
 
+    def rank_touches(self, card_rank: int, clue_rank: int) -> bool:
+        match self.rank_clues:
+            case ClueBehaviour.none:
+                return False
+            case ClueBehaviour.default:
+                return card_rank == clue_rank
+            case ClueBehaviour.all:
+                return True
+
+    def color_touches(self, clue_color: int) -> bool:
+        match self.color_clues:
+            case ClueBehaviour.none:
+                return False
+            case ClueBehaviour.default:
+                return clue_color in self.colors
+            case ClueBehaviour.all:
+                return True
+
     def __str__(self):
         return self.name
 
@@ -83,21 +101,21 @@ class Variant:
         self.name = name
         self.clue_starved = clue_starved
         self.throw_it_in_a_hole = throw_it_in_a_hole
-        self.alternating_clues = alternating_clues
-        self.synesthesia = synesthesia
-        self.chimneys = chimneys
-        self.funnels = funnels
-        self.no_color_clues = no_color_clues
-        self.no_rank_clues = no_rank_clues
-        self.empty_color_clues = empty_color_clues
-        self.empty_rank_clues = empty_rank_clues
-        self.odds_and_evens = odds_and_evens
-        self.up_or_down = up_or_down
+        self.alternating_clues = alternating_clues  # TODO: has to be somehow supported by game itself
+        self.synesthesia = synesthesia  #
+        self.chimneys = chimneys  #
+        self.funnels = funnels  #
+        self.no_color_clues = no_color_clues  #
+        self.no_rank_clues = no_rank_clues  #
+        self.empty_color_clues = empty_color_clues  #
+        self.empty_rank_clues = empty_rank_clues  #
+        self.odds_and_evens = odds_and_evens  #
+        self.up_or_down = up_or_down  # TODO: currently not supported
         self.critical_fours = critical_fours
         self.num_suits = len(suits)
-        self.special_rank = special_rank
-        self.special_rank_ranks = special_rank_ranks
-        self.special_rank_colors = special_rank_colors
+        self.special_rank = special_rank  #
+        self.special_rank_ranks = special_rank_ranks  #
+        self.special_rank_colors = special_rank_colors  #
         self.special_deceptive = special_deceptive
 
         self.suits = suits
@@ -123,8 +141,76 @@ class Variant:
 
         self.num_colors = len(self.colors)
 
+    def _preprocess_rank(self, value: int) -> List[int]:
+        if self.empty_rank_clues:
+            return []
+        if self.chimneys:
+            return [rank for rank in self.ranks if rank >= value]
+        if self.funnels:
+            return [rank for rank in self.ranks if rank <= value]
+        if self.odds_and_evens:
+            return [rank for rank in self.ranks if (rank - value) % 2 == 0]
+        return [value]
+
+    def _synesthesia_ranks(self, color_value: int) -> List[int]:
+        return [rank for rank in self.ranks if (rank - color_value) % len(self.colors) == 0]
+
     def rank_touches(self, card: DeckCard, value: int):
-        pass
+        assert 0 <= card.suitIndex < self.num_suits,\
+            f"Unexpected card {card}, suitIndex {card.suitIndex} out of bounds for {self.num_suits} suits."
+        assert not self.no_rank_clues, "Cluing rank not allowed in this variant."
+        assert value in self.ranks, f"Cluing value {value} not allowed in this variant."
+
+        if self.special_rank is not None and self.special_rank_ranks != ClueBehaviour.default:
+            suit = self.suits[card.suitIndex]
+            match suit.rank_clues:
+                case ClueBehaviour.none:
+                    return False
+                case ClueBehaviour.default:
+                    match self.special_rank_ranks:
+                        case ClueBehaviour.none:
+                            return False
+                        case ClueBehaviour.default:
+                            assert False, "Programming error"
+                        case ClueBehaviour.all:
+                            return True
+                case ClueBehaviour.all:
+                    return True
+
+        ranks = self._preprocess_rank(value)
+        return any(self.suits[card.suitIndex].rank_touches(card.rank, rank) for rank in ranks)
+
+    def color_touches(self, card: DeckCard, value: int):
+        assert 0 <= card.suitIndex < self.num_suits, \
+            f"Unexpected card {card}, suitIndex {card.suitIndex} out of bounds for {self.num_suits} suits."
+        assert not self.no_color_clues, "Cluing color not allowed in this variant."
+        assert 0 <= value < len(self.colors), f"Color clue with index {value} does not exist in this variant."
+
+        if self.special_rank is not None and self.special_rank_colors != ClueBehaviour.default:
+            suit = self.suits[card.suitIndex]
+            match suit.color_clues:
+                case ClueBehaviour.none:
+                    return False
+                case ClueBehaviour.default:
+                    match self.special_rank_colors:
+                        case ClueBehaviour.none:
+                            return False
+                        case ClueBehaviour.default:
+                            assert False, "Programming error"
+                        case ClueBehaviour.all:
+                            return True
+                case ClueBehaviour.all:
+                    return True
+
+        if self.empty_color_clues:
+            return False
+        if self.synesthesia and any(self.rank_touches(card, rank_val) for rank_val in self._synesthesia_ranks(value)):
+            return True
+
+        suit = self.suits[card.suitIndex]
+        if suit.prism and value == ((card.rank - 1) % len(self.colors)):
+            return True
+        return suit.color_touches(self.colors[value])
 
     @staticmethod
     def from_db(var_id):