The Korean word "poom-sae" means a "form" or "pattern of movements." It is actually a planned series of movements that combines the physical skills (such as blocks, strikes, kicks, stances and more) with the mental skills (such as balance, coordination, discipline, strategy, focus and more). The target of these movements is an imaginary opponent of the practitioner's own size.
The copyrighted Songahm forms have been arranged as a system to gradually increase the student's skill, develop technical balance equally on the left and right side of the body, train muscles, and to develop students from the beginner level through the rank of Grand Master. This is why each Songahm form does not repeat most techniques more than twice and also why every technique which is done with a right arm/leg is also repeated with the left arm/leg.
These forms, designed by Eternal Grand Master H.U. Lee, were the first that truly emphasized the tradition of the art of Taekwondo, unlike older forms (hyung) which were based on Japanese and Okinawan Karate forms. Not only do the Songahm forms train you in each rank, but they are also excellent for using as a warm-up prior to a work out.
The "system" that encompasses the 18 Songahm forms is based on traditional philosophy, as well as being designed for easy memorization.