he True Strength Index (TSI) is a popular and useful forex indicator that is available for free on the MetaTrader 4 (MT4) trading platform. The TSI is a momentum-based oscillator that measures the rate of change of a security’s price. The indicator is based on two moving averages that are calculated using the close, high, and low prices of the security. The TSI is calculated by subtracting the lower moving average from the higher moving average. It is a great indicator for traders looking to enter or exit positions in the forex market.