Satori Center

From the book Effective Horsemanship by Noel Jackson, comes this really handy chart:
 

These rein aids are considered a bit more high level and require the horse is going forward in strong impulsion.

• Rein (1) - red - direct rein of opposition - swings the butt away
• Rein (2) - blue - indirect rein of opposition - swings the shoulders away
• Rein (3) - purple - intermediary rein - produces lateral march

I would add it's important to also always have a soft, supportive, oscillating contact with the reins.  

A traditional and comprehensive approach from the Cadre Noir.