DESCRIPTION:
Here's a simple trick I use all the time to use D and Bm in middle of guitar. It's useful because you can use the open D string , while transforming your D chord into B with adding bass note.

Often, I use this as build up from open chords, or to be able to have access to higher notes from middle of neck.

It's also easy to access A major from this position on neck and you can use open A string.

Using open strings allows you to have smooth transitions when making jumps around the neck. D major (along with E minor, A major) are great keys for this.

Good luck!