Sonata form (also called "sonata-allegro form") is a musical debate vvithin a single
movement based on the conflict and ultimate resolution of tvvo opposing key centers.
Sonata form is the First movement form of virtually every Classic instrumental work,
though It may be used in other movements as vvell.) This unigue Classic form has
three distinct dramatic aspects vvithin a binary harmonic plan:
Expositio (Tonal Opposition)
The two opposing key centers (and associated themes) are introduced:
Thome 1 is in the 'home" key; Thome 2 is in a different key.
Development (Escalation of tension)
The material passes rapidly through many distant keys, and may be fragmented/reworked in a
variety of ways.
Recapitulation (Tonal Resolution)
Thome 1 and Thome 2 both appear in the 'home" key. (In the tradition of Classic debate, Theme
2 realizes its weaker stance, and wholeheartedly throws its support to its opponent's stronger
argument—the "home' key.)