WD Gann’s Approximate time of development
1902. Started trading.
1909. WD Gann started making public predictions using the name Orlo. In September he demonstrated his method for The Ticker Magazine and introduced his concepts based around the Law of Vibration, History repeats, the number 7.
These were continuously used and developed further in all Ganns later work.
There is no reason to believe that the Gann angles or astrology are evidenced in the Ticker interview.
1919. Annual Forecasts. Perhaps began as early as 1915.
1921. Astrology is mentioned for the first time in an interview. Philadelphia Journal of Commerce January 15, 1921.
“His calculations are based on the science of letters, numbers [law of vibration] and Astrology.”
1909-1923. Main calculators? An Interview with WD Gann – New York Herald. 1923.
“He has a big, ponderous volume filled with these figures – squares, angles, pyramids and circles – and whenever he wants to know anything he turns to a certain geometrical figure and puts his finger on the answer.”
1923. First book “Truth of the Stock Tape” published.
1927. “THE TUNNEL THRU THE AIR or LOOKING BACK FROM 1940”. published [also referred to in this book as TTTA or Tunnel]
Explains in more detail all the principles from the Ticker (1909) interview as well as more detail on Astrology.
1931-35 First trading courses for private students.
Name Vibration charts.
The New York Stock Exchange
United States Steel.
Square of the number 9.
Square of the number 12.
Square of the number 360
Square of the high or low price.
Square of the range.
Square of 52.
Square of 90.
Square of 144.
Price and Time Calculators.
Spiral/Octagon chart (now commonly called the square of nine)
Square of four.
Circle chart. (Wheel of 24)
1937. “How to trade in Puts and Calls”
The earliest reference to the 50% rule.
1939. “Review of Dow Bull & Bear Markets 1909-1939”
50% rule again mentioned.
1942. How to make profits trading in commodities. [revised and updated 1951]
Work on percentages fully developed.
1940s. Earliest reference (that I can find to planetary angles)
These may have been under development in the 1930’s but were definitely expanded on in the 1940-50s.
To recap, the methods were likely discovered in the following order.
Law of Vibration / History repeats
Gann angles. I am unsure of the timing of this but by 1931 most of the things we know about Ganns methods were in use, except for the two later developments, the 50% rule (percentages) and planetary support and resistance lines.