Which venue did Kolkata Knight Riders play most of their matches as a Team 1?
venue refers to Venue_Name; Kolkata Knight Riders refers to Team_Name = 'Kolkata Knight Riders'; most of their matches refers to max(count(Venue_Id)); Team 1 refers to Team_Id = Team_1
SELECT T3.Venue_Name FROM Team AS T1 INNER JOIN Match AS T2 ON T1.Team_Id = T2.Team_1 INNER JOIN Venue AS T3 ON T2.Venue_Id = T3.Venue_Id WHERE T1.Team_Name = 'Kolkata Knight Riders' GROUP BY T3.Venue_Id ORDER BY COUNT(T3.Venue_Id) DESC LIMIT 1