Tristan Chord for Guitar

Today's Guitar Chord of the Day is the famous 'Tristan' chord from Wagner's Tristan und Isolde. The fingering of this guitar chord is not unusual as it has the same fingering as a m7b5 chord/9th chord.

The chord can be played on the middle four strings of the guitar:

The way it's used is more unusual: here it functions as a dissonant chord that resolves chromatically to an E dominant 7th chord

 

Here's the passage in guitar tablature:

You can hear a midi file version of this extract here.