Trading Rule #19

This script is based on Trading Rule #19 from Chester Keltner's book How To Make Money On Commodities. It is best applied to candlestick charts with longer time frames and plans with minimal losses (i.e. swing trades). The rule is based on "Key" trend days (this is applied to daily charts in the book).

An initial Key-Up day is established on the third day of 3 consecutive new highs. Subsequent key-up days are determined as follows:
1. The first day following an initial key-up day trades 0.375% above the previous key-up day
2. The second day or any following day trades 0.125% above the previous key-up day

An initial Key-Down day is established on the third day of 3 consecutive new lows. Subsequent key-down days are determined as follows:
1. The first day following an initial key-up day trades 0.375% below the previous key-down day
2. The second day or any following day trades 0.125% below the previous key-down day

Green candles are considered up-trend, red candles are down-trend. Gray candles are undecided - when there is a new high and low in the same time frame, when there is no new high or low in that time frame, or the order price was cleared.

Order prices are represented as a blue line, with some days being "na" when order prices remain unchanged. On key-up days, orders are placed 0.375% below the low of the previous key-up day or the day previous (whichever is lower). Order prices on key-down days are placed 0.375% above the high of the previous key-down day or the day previous (whichever is higher).

The tolerance setting mainly effects the plot point of order price, at a certain point key-trend rules will take priority over order price (meaning if tolerance is high enough, order price will have no effect on determining key-trends).