Module 1 gave you the idea: the market auctions up and down, searching for where business gets done. The problem is that a normal candlestick chart shows that search sideways through time, which buries the answer. The Market Profile — developed by J. Peter Steidlmayer at the Chicago Board of Trade and introduced publicly in 1985 — rotates the question: instead of "where did price go?", it asks "how much time did the market spend at each price?"
How the graphic is built
The mechanics are simple bookkeeping. The session is cut into half-hour brackets, and each bracket gets a letter — A for the first, B for the second, and so on. Every price the market touches during a bracket prints that bracket's letter at that price. One letter at one price is a TPO — a Time-Price Opportunity, which the original CBOT manual defined as an "opportunity created by the market at a certain price at a certain time."
1125 B C
1100 B C D
1075 A B C D E
1050 A B C D E F ← fattest row: most time spent
1025 A E F
1000 A
Stack the letters and the day organizes itself: prices the auction kept returning to grow long rows; prices it visited once and refused stay single letters. In a balanced session the result is a bell shape — fat in the middle where two-sided trade concentrated, thin at the extremes where one side shut the auction off. Steidlmayer's insight was recognizing this as the normal distribution from basic statistics, occurring live in the pit, every day.
What the shape already tells you
Even before any named reference points, the silhouette speaks. A fat, symmetric profile says the auction found a price everyone could do business around — balance. A tall, thin profile says price kept moving and never built acceptance anywhere — a trend, with one side in control all day. Thin tails at the top or bottom mark prices the market tried and emphatically refused. You are looking at the auction's memory of the day: every advertisement, acceptance, and rejection from Module 1, in one picture.
One honest footnote before you fall in love with it: the classic Profile counts time, not volume. Time at price and volume at price usually agree — but they are not the same measurement, and the modern volume profile measures conviction directly. We treat that distinction fully in the reference page and again in Module 8.
Assignment
Open a Market Profile (or TPO) chart on your platform — nearly all modern platforms include one — on the same market you watched for Module 1. Don't trade anything. For three sessions, do one thing at the close: describe the day's shape in a sentence. "Fat and symmetric." "Thin and stretched higher." "Fat base, one thin probe up that failed." When your sentences start writing themselves, you're reading structure — and you're ready to ask the Profile its most valuable question, which is Module 3.