Spider chord

The spider chord is a guitar technique popularized during the 80s thrash metal scene. Regarded as being popularized (and the term "spider chord" coined) by Dave Mustaine of Megadeth, it is used to reduce string noise when playing (mostly chromatic) riffs which require chords across several strings.

The chord or technique is used in the songs "Wake Up Dead", "Holy Wars... The Punishment Due" and "Ride the Lightning".^[1]

Technique

   D5 Bb5
e|-------|
B|-------|
G|-------|
D|-7-----|
A|-5--8--|
E|----6--|
   3      <
   1  4   <--Spider chord fingering
      2   <

As seen in the above tab, the two power chords may be played in succession without shifting, making it easier and quicker^[1], and thus avoiding string noise. The normal fingering would be for both chords, requiring a simultaneous shift and string change. Note that the two power chords are a major third apart, if the first chord is the tonic the second is the minor submediant. The spider chord fingering also allows access to a major seventh chord without the third:^[1]

    AM7
e|------|
B|------|
G|------|
D|--6---|
A|--7---|
E|--5---|
    3
    4
    2

The spider chord requires the player to use all four fingers of the fretting hand, thus its name. This technique then allows you to run down the neck playing either of the two chords.^[1]

Sources