Thursday evening in a Shimokitazawa basement, the Gento Gekijo troupe shows Waltz for Daddy, a magic-lantern theater piece in the projected-image tradition that predates cinema in this country and never quite died with it. Tickets run 2,000 yen general, 1,500 under 30, 1,000 under 22. A small room, an old form kept working. Worth the seat.