A Brahms classical guitar has eight strings, an additional bass string tuned lower than the sixth string and an additional treble string tuned higher than the first (or in this case, the second string). This extends the musical range of the guitar, it was originally designed to play transcriptions of piano works of Johannes Brahms.
In order for all this to work, the guitar must be a “multi-scale” guitar. The bass string spans, from nut to saddle, 650mm and the high treble string spans 615mm (it can be shorter), the shorter distance allows the treble string to be brought up to concert pitch without breaking.
This makes the bridge angle across the soundboard, by pushing the slot for the saddle back from the edge of the bridge, this allows the bridge to be less angled across the soundboard. This makes the transference of sound energy more efficient.