Mission's Live Music Bar

Turn right out of North exit of Koenji station and follow the street past the police box and Tokyu supermarket. Keep walking for 1-2 minutes, passing Family Mart on the way, and here is Mission livehouse.
Wash Club is next door, which isn't a club, just a launderette...nice name though.

http://www.live-missions.com/

They happen to have a shit load of bottled liquor.
1 drink is 500 yen, but they do 3 drinks for 1000 yen later in the night.
They serve a generous helping of whiskey, which is nice.