'The Rule of Six' from 'In the Blink of an Eye'

Walter Murch discusses what makes a good edit, and details the way the craft has changed with developments in technology.

The ideal moment to cut is dictated by six elements, which are in a hierarchy of importance, such that the ones lower down the list should be sacrificed before those above them (editing requires compromise).

1. Most important is Emotion.  The cut needs to conform to the emotion of the moment.  I'm not exactly sure what this means as there were no examples given.
2. Story comes next.  I would have thought this would come at the top - if the edit doesn't advance the story, it is redundant, and that is bad in principle.
3. Where you cut is also determined by rhythm - the point needs to be 'rhythmically interesting and right'.  I think this is closely related to pace.
4. Something I had not considered before, and is particularly apposite for editing material for the 'big screen', is eye-trace.  Every edit has a focus of interest, and this is where the viewer's eye is drawn to when they watch a film in the cinema.  This can often be the eyes of a character.  The edit that follows must not be too far from the previous focus of interest, or the viewer will become disoriented (unless this is the effect wanted).
5. An edit must respect the two-dimensional plane of the screen, or 'planarity'.  This is basically the grammar of three dimensions transposed to two, i.e. not crossing the 180 degree line, 'stage line'.
6. Finally, the three-dimensional space of action - an edit should respect the three-dimensional continuity of the actual space, where people are standing in a room in relation to each other.

So this is the list of priorities.  Murch add a percentage of importance to each one, such that the top three are by far the most important, such that the lower ones can be violated without much cost as long as emotion, story and rhythm are satisfied.  He also stresses that no higher priorities should be sacrificed for lower ones. So, to summarise ;

1. EMOTION          51%
2. STORY               23%
3. RHYTHM           10%
4. EYE - TRACE                                                          7%
5. TWO - DIMENSIONAL PLANE OF SPACE         5%
6. THREE - DIMENSIONAL SPACE OF ACTION   4%

Of course, all this only applies to Murch's Hollywood based movies - 'The Conversation',  'American Graffiti',  'Apocalypse Now', 'The Godfather' franchise, 'The Unbearable Lightness of Being', 'The English Patient', 'The Talented Mr. Ripley'.  However, it is all grist for the mill of someone interested in the craft.