Yamaha Beginner Classical Neck Relief.

Blaendulais

ICBM said:

Relief is not the same as action. Relief is the curvature of the neck, allowing a small gap between the strings and the frets in the middle, to allow for the arc of the string vibration. Action is the height of the strings above the fingerboard, and is mostly a function of the bridge height.

Usually, classical guitars do not have and do not need adjustable relief, because the string tension isn't high enough to affect the curvature of the neck much - they usually have a fixed reinforcement bar, usually metal but sometimes a much stiffer wood (normally ebony) or carbon fibre on some high-end modern ones. There may be a tiny amount of relief even then, which is ideal. Check by holding the guitar normally and fretting the G string at the first and 13th frets. There should be a very small gap between the string and the 7th fret, about the thickness of a thick piece of paper.

The bridge height is usually much higher than on a steel-string acoustic, in order to enable the lower-tension strings to be played cleanly. But not ridiculously high - the height you need to check is at the 12th fret, not over the body - as Mellish said, many classicals have intentional 'fall away' planed into the fingerboard above the body joint, to further enable string movement. It should usually be about 3-4mm at the 12th fret, or about double that of a steel-string. If it's a lot higher than that, either the saddle is too tall, the bridge has started to lift (check for a gap under the back edge), the top is pulling up (sight across the guitar sideways and look at the angle of the bridge/body join relative to the edge of the guitar), or the neck joint has shifted - almost always due to wood shrinkage. If the saddle sticks up more than about 2mm above the bridge itself, it can possibly be lowered - but not to less than about 1mm above.

More excellent ICBM wisdom thanks @ICBM I keep learning from you

tekbow

ICBM said:

Relief is not the same as action. Relief is the curvature of the neck, allowing a small gap between the strings and the frets in the middle, to allow for the arc of the string vibration. Action is the height of the strings above the fingerboard, and is mostly a function of the bridge height.

Usually, classical guitars do not have and do not need adjustable relief, because the string tension isn't high enough to affect the curvature of the neck much - they usually have a fixed reinforcement bar, usually metal but sometimes a much stiffer wood (normally ebony) or carbon fibre on some high-end modern ones. There may be a tiny amount of relief even then, which is ideal. Check by holding the guitar normally and fretting the G string at the first and 13th frets. There should be a very small gap between the string and the 7th fret, about the thickness of a thick piece of paper.

The bridge height is usually much higher than on a steel-string acoustic, in order to enable the lower-tension strings to be played cleanly. But not ridiculously high - the height you need to check is at the 12th fret, not over the body - as Mellish said, many classicals have intentional 'fall away' planed into the fingerboard above the body joint, to further enable string movement. It should usually be about 3-4mm at the 12th fret, or about double that of a steel-string. If it's a lot higher than that, either the saddle is too tall, the bridge has started to lift (check for a gap under the back edge), the top is pulling up (sight across the guitar sideways and look at the angle of the bridge/body join relative to the edge of the guitar), or the neck joint has shifted - almost always due to wood shrinkage. If the saddle sticks up more than about 2mm above the bridge itself, it can possibly be lowered - but not to less than about 1mm above.

Ok so, from a few descriptions, this does seem to be intended fall away, I'll take a closer look at it next time I'm over.

On the topic of nut Slots, I don't think this is the issue, if there even is an issue, as the guitar is absolutely fine action wise lower down the neck.