The title track's driving, harmonized riff. Dave Murray drove his black Stratocaster — a DiMarzio Super Distortion in the bridge — and Adrian Smith his red Ibanez Destroyer (the guitar Smith said he 'recorded Number of the Beast on, the song, the solo, and everything') into cranked Marshalls, with an MXR Distortion+ adding the singing lead bite. Martin Birch tracked the twin parts at Battery Studios, London. Standard tuning; the aggression is in the picking hand and a tight gate.