1. The law of supply and demand determines the price direction. This principle is central to Wyckoff’s method of trading and investing. When demand is greater than supply, prices rise, and when supply is greater than demand, prices fall. The trader/analyst can study the balance between supply and demand by comparing price and volume bars over time. This law is deceptively simple, but learning to accurately evaluate supply and demand on bar charts and to understand the implications of supply and demand patterns takes considerable practice.