diff --git a/src/mahjong_ranking/managers.py b/src/mahjong_ranking/managers.py
index 58cc202..1ed70f8 100644
--- a/src/mahjong_ranking/managers.py
+++ b/src/mahjong_ranking/managers.py
@@ -16,7 +16,9 @@ class HanchanManager(models.Manager):
     def confirmed_hanchans(self, user=None, since=None, until=None, **filter_args):
         """ Return all valid and confirmed Hanchans. 
         
-        :param user: Only return Hanchans where this user participated.  
+        :param user: Only return Hanchans where this user participated.
+        :param since: only return Hanchans played since the given datetime
+        :param until: only return Hanchans played until the given datetime
         :param filter_args: To add specific arguments to the Django filter.
         :return: QuerySet Object
         """
@@ -35,6 +37,7 @@ class HanchanManager(models.Manager):
         gain dan points and make his gamestats availabale.
 
         :param user: Only return Hanchans where this user participated.  
+        :param since: only return Hanchans played since the given datetime
         :param filter_args: To add specific arguments to the Django filter.
         :return: QuerySet Object
         """
@@ -55,6 +58,7 @@ class HanchanManager(models.Manager):
         gain kyū points and make his gamestats availabale.
 
         :param user: Only return Hanchans where this user participated.  
+        :param since: only return Hanchans played since the given datetime
         :param filter_args: To add specific arguments to the Django filter.
         :return: QuerySet Object
         """
@@ -87,7 +91,7 @@ class HanchanManager(models.Manager):
         """Return all Hanchans where a specific user has participated. 
 
         :param user: Return Hanchans where this user participated.  
-        :param since: optional a date value since when you want to hanchans
+        :param since: only return Hanchans played since the given datetime
         :param filter_args: To add specific arguments to the Django filter.
         :return: a QuerySet Object
         """