Take the South-east exit of Shinjuku station, walk along Kousyuukaidou (The big road. You'll see Tower Records on the left of it and Takashimaya Times Square on the right) until you reach Meiji-dori. Turn right (you should see a Yoshinoya on the corner) and walk along Meiji-dori. Antiknock is on the left hand side in the basement of the Ray Flat building.
Map

LiveHouse Map video directions