diff --git a/gamedata.cpp b/gamedata.cpp
index 1e2c074..a3364fc 100644
--- a/gamedata.cpp
+++ b/gamedata.cpp
@@ -71,6 +71,13 @@ void GameData::toggle_turn()
 	}
     }
 
+    for (list<Vertex*>::iterator cursor = vertices.begin();
+	 cursor != vertices.end(); cursor++)
+    {
+	GameVertex* v = dynamic_cast<GameVertex*>(*cursor);
+	v->attacked = false;
+    }
+
     current = NULL;
 }
 
@@ -246,16 +253,21 @@ int GameData::get_range(GameVertex* node)
 
 void GameData::attack_vertex(GameVertex* target)
 {
-    float atk = current->calculate_attack();
-    float armor = target->calculate_armor();
-    int damage = (int)(atk / armor);
-    target->score -= damage;
-    if (target->score <= 0) remove_vertex(target);
-
+    if (!current->attacked)
+    {
+	float atk = current->calculate_attack();
+	float armor = target->calculate_armor();
+	int damage = (int)(atk / armor);
+	target->score -= damage;
+	if (target->score <= 0) remove_vertex(target);
+	current->attacked = true;
+	
 #ifdef DEBUG
-    fprintf(stderr, "debug: GameData::attack_vertex(): atk=%.2f, armor=%.2f, damage=%d\n", atk, armor, damage);
+	fprintf(stderr, "debug: GameData::attack_vertex(): atk=%.2f, armor=%.2f, damage=%d\n", atk, armor, damage);
 #endif
 
+    }
+
     mode = MODE_SELECT;
 }
 
diff --git a/gamevertex.h b/gamevertex.h
index 314f9d4..ba597d5 100644
--- a/gamevertex.h
+++ b/gamevertex.h
@@ -23,6 +23,7 @@ class GameVertex : public Vertex
 
     VertexType type;
     Player* player;
+    bool attacked; // only applicable for a VERTEX_ATTACKER
 
     float calculate_attack();
     float calculate_armor();