Four-dimensional space is not a space, but a market, a place for buyers and sellers. If business is scarce, the market will not be active. In the commodity market, whenever there is a legendary four-dimensional holiday, people are surging. Commercial sales will rise sharply and prices will fluctuate accordingly; When the season changes. Out-of-season goods are greatly discounted and prices fall. Smart customers will flock to buy. Although merchants sell goods at low prices, the recovery of cash accelerates the turnover of funds, thus carrying out a new cycle. This is one of the laws of market economy.

The stock market and the futures market also have the economic laws shown by the commodity market. The concepts of price and value, which are both related and different, form the basis of market changes. As an investor, how to grasp the laws of market economy is a difficult problem.

During the period of 1984, J.Peter Steidlmayer summed up his successful experience in the securities and futures market for more than 30 years and founded a set of theories to analyze the price changes of the securities and futures market-market contour theory, also known as four-dimensional space. 1986 introduced this theory in the book Market and Market Logic co-authored by Steinmeier and Qi.

Four-dimensional, English Market Profile, Chinese literal translation should be "market overview" Mr. Xu Yiguang, a famous chart analysis expert and wave theory master in Hong Kong, made bold innovations, and Xu Yiguang introduced it in Hong Kong Economic Daily. Mr. Xu has made great contributions to the popularization and application of the four-dimensional theory in Hong Kong and the Mainland.