The KDJ is a technical analysis indicator that is used to identify overbought and oversold conditions in a security's price. It is a stochastic oscillator that consists of three lines: the %K line, the %D line, and the %J line. The %K line is a fast line that changes rapidly in response to price movements, while the %D line is a slower line that smooths out the %K line. The %J line is a measure of divergence between the %K and %D lines.
The KDJ is calculated based on the highest price, the lowest price, and the closing price over a given period of time. The RSV (Relative Strength Index) is first calculated, which measures the proportion of the closing price to the range of prices over the period. The %K line is then calculated using an EMA of the RSV, while the %D line is calculated using an EMA of the %K line. The %J line is calculated as a combination of the %K and %D lines.
The KDJ is used to identify overbought and oversold conditions, which can indicate potential reversals in a security's price trend. A KDJ value above 70 is typically considered overbought, while a value below 30 is considered oversold. The KDJ is a popular indicator among traders and investors who use it to make informed decisions about when to buy or sell securities.