True Strength Indicator
Developed in the early 1990s by William Blau. It is used to identify the direction of the market and any overbought/oversold conditions. When the two lines cross above the zero line then an upward direction is assumed. Similarly, when they cross below the zero line a downtrend is implied. When a sharp peak is formed by the lines above zero, an overbought reading is registered. On the other hand, when a sharp trough is formed below zero, an oversold condition is recorded.